Chapter XXVI: Introduction: General Characters and Terminology—brown Bodies—history (3)

{One or more of the following characters: orifice provided with an
{ operculum; avicularia or vibracula present; a globular ovicell
{ above the orifice of certain zooecia (CHEILOSTOMATA) 7
{
{Opercula, avicularia, vibracula, and ovicells completely absent,
{ or inconspicuous. Calcareous or non-calcareous. If calcareous,
1. { the orifice is not at the end of a free cylindrical portion 3
{
{Calcareous; zooecia cylindrical, often united for the greater part
{ of their length, but usually ending in a free cylindrical
{ portion,which bears the terminal orifice. The zooecia may be
{ much obscured by calcifications surrounding their basal parts 2

{Zooecia long, tubular, with a lateral membranous region at the upper
{ end, given off quite separately from a creeping stolon _Aetea_
2. {
{Zooecia more or less united to one another, orifice without
{ chitinous operculum (CYCLOSTOMATA[601]) 63

{Zooecia without marginal spines; arising from a branching axis,
{ which is not formed of zooecia 74
{
3. {Colony adherent; _or_ erect, fleshy and slightly branched; _or_
{ erect, encrusted with earthy matter and repeatedly branched 72
{
{Characters not as above 4

{Zooecia minute, boat-shaped, united by a delicate tube. Aperture
4. { large, with marginal spines _Beania mirabilis_
{
{Colony delicate, erect; zooecia wider above than below 5

{No marginal spines 6
{
5. {Zooecia uniserial; with marginal spines. Branches arising from
{ the top of a zooecium _Brettia_

{Zooecia uniserial; branches arising just below the large aperture. An
{ ovicell may be developed above the orifice of a modified zooecium
6. { _Eucratea chelata_
{
{Zooecia somewhat pear-shaped; orifice small, semicircular
{ _Huxleya fragilis_

{526}
{Colony erect 8
{
7. {Zooecia in several layers forming confused masses 30
{
{Colony entirely adherent,[602] the zooecia usually in a single
{ layer 31

ERECT CHEILOSTOMATA.

{Branches cylindrical, calcareous, divided by chitinous joints.
{ Orifices arranged all round the branc _Cellaria_ (Fig. 239, A)
{
8. {Branches flexible, jointed or unjointed. Orifices not arranged
{ all round the branch. 9
{
{Calcareous, unjointed, rigid 21

{Branches leaf-like, flattened 10
9. {
{Branches not leaf-like 11

{Avicularia resembling birds' heads, movable _Bugula_ (Fig. 233)
{
10.{Avicularia not resembling birds' heads, unstalked; _or_ absent.
{ Colony broadly leaf-shaped, composed of a single layer or of
{ two layers of zooecia _Flustra_ (Fig. 232)

{Zooecia in pairs, at the same level 12
11.{
{Zooecia not obviously paired 13

{Branches numerous, straight. Zooecia back to back, with an oblique
{ aperture. No avicularia _Gemellaria loricata_
12.{
{Branches delicate, curved. A pair of stalked avicularia between
{ each two pairs of zooecia _Notamia_ (_= Epistomia_) _bursaria_

{conspicuous 14
13. Avicularia or vibracula {
{inconspicuous or absent 17

{Avicularia resembling birds' heads, movable. Vibracula absent 15
{
{Avicularia large, unstalked. Vibracula present or absent 16
14.{
{Avicularia inconspicuous. Setae of the vibracula large, very
{ conspicuous, on oblique vibracular zooecia, which almost cover
{ the backs of the branches _Caberea_ (Fig. 242)

{Zooecia in two series, alternate, with one or several
{ conspicuously long marginal spines _Bicellaria_
15.{
{Zooecia in two or more series. Aperture occupying most of the
{ front of the zooecium. Colony often spiral. Avicularia
{ usually large _Bugula_ (Fig. 233)

{Zooecia long, narrow below, commonly in triplets, with two lateral
{ avicularia to each triplet. Fornix present. _Menipea ternata_
{
16.{Zooecia biserial, a considerable number forming an internode
{ separated by a joint (often inconspicuous) from the next
{ internode. Lateral avicularia usually large. Vibracular zooecia
{ on the back or sides of the branches _Scrupocellaria_ (Fig. 254)

{Characters as in _Scrupocellaria_ (No. 16), but with inconspicuous
17.{ avicularia. A branched fornix _Scrupocellaria reptans_
{
{Vibracula absent 18

{A single, short, marginal spine; _or_ none 19
18.{
{Marginal spines present 20

{527}
{Characters as in No. 6 _Eucratea chelata_,
{ _Huxleya fragilis_
{
{Zooecia biserial. Aperture large, the semicircular orifice at its
{ upper end, where there is commonly a short spine
{ _Cellularia peachii_
19.{
{Zooecia in one or two series. Branches originating from the backs
{ of the zooecia, and facing in the opposite direction to the
{ parent branch. Aperture small _Scruparia clavata_

{One or more conspicuously long marginal spines. Avicularia
{ present or absent _Bicellaria_
{
20.{Zooecia uniserial (see No. 5) _Brettia_
{
{Zooecia biserial, in short internodes. An inconspicuous avicularium
{ below the aperture. Fornix present _Menipea jeffreysii_

{Colony consisting of a network of narrow branches, the zooecia
{ opening only on one of their surfaces _Retepora_
{
{Colony large, brittle, composed of contorted plates, uniting
21.{ irregularly, usually composed of two layers of zooecia.
{ Orifice large, indented laterally _Lepralia foliacea_
{
{Branches delicate, cylindrical 22
{
{Branches or lobes coarser, not necessarily cylindrical 24

{Branches composed of four rows of zooecia 23
{
22.{Zooecia in more than four regular, longitudinal rows. Peristome
{ raised, and, with the ovicell, forming a swelling on the
{ surface of the branch _Escharoides quincuncialis_

{Orifice circular. A row of pores round the margin of the zooecium.
{ A median pore resembling a small orifice below the true orifice.
23.{ Small lateral avicularia _Porina borealis_
{
{Orifice surrounded by a peristome, produced into a mucro beneath
{ the orifice. No pores _Palmicellaria elegans_

{Zooecia arranged in regular series 25
{
24.{Zooecia irregularly heaped, their long axes often perpendicular
{ to the surface of the colony. Mucro largely developed,
{ concealing the form of the orifice, and bearing an avicularium
{ _Cellepora_

{Orifice with a sinus; _or_ peristome interrupted or extended below
25.{ into a sinus-like outgrowth, which usually includes a small
{ avicularium 26
{
{Neither median sinus nor interrupted or extended peristome 28

{Orifice with a sinus _Schizoporella_ (Fig. 239, B)
26.{
{Peristome interrupted or extended below 27

{Branches of various forms. Surface of the older parts very even.
{ Secondary orifice rather long, usually wider above, enclosing a
{ small avicularium below, and appearing as a hole in the even
{ surface of the branch _Porella_ (Fig. 255, B, C)
{
27.{A prominent tooth projects into the orifice from its lower side.
{ Zooecia with thin walls _Smittia landsborovii_ (Fig. 239, C)
{
{No tooth in the orifice, at the side of which is a small avicularium.
{ Old zooecia with thick walls. Colony composed of a short stem
{ and flattened branches _Escharoides rosacea_

{A tooth projects from the lower side into the large, {528}
{ subcircular orifice, on each side of which is a small oval
28.{ avicularium (colony erect or encrusting) _Mucronella pavonella_
{
{No tooth: mucro sometimes present 29

{Branches cylindrical. Old zooecia with thick walls. Orifice in
{ young zooecia longer than broad; beneath it a median pore,
29.{ and in some cases a lateral avicularium with vibraculoid mandible
{ _Diporula verrucosa_
{A distinct mucro, which may bear an avicularium above
{ _Palmicellaria_

ENCRUSTING CHEILOSTOMATA.

{Usually growing on a small univalve shell. Orifice longer than
{ broad, indented laterally. Mucro present _Lepralia edax_
{
30.{One or two conspicuous processes, each bearing an avicularium,
{ near the orifice, which is often concealed. Avicularia in many
{ cases found on other parts of the colony _Cellepora_

{Zooecia distant; _or_ in single rows 32
31.{
{Zooecia forming continuous expansions 36

{An oval aperture, larger than the orifice 33
32.{
{No aperture 34

{A tubular process below the aperture, in some cases: zooecia very
33.{ narrow below _Eucratea chelata_, var. _repens_
{
{No tubular process below the aperture _Membranipora_

{Peristome much raised below, collar-like _Phylactella_
34.{
{Peristome not much raised below 35

{Zooecia minute, much narrowed below. Orifice small, usually with
35.{ a sinus _Hippothoa_
{
{Zooecia not narrowed below. Orifice with a sinus _Schizoporella_

{Zooecia partly separated by a thin calcareous crust. Colonies
36.{ small 37
{
{Zooecia contiguous 38

{Zooecia pear-shaped. Orifice with a sinus _Hippothoa expansa_
{
37.{Zooecia ovoid. Orifice subcircular, with a tubular peristome
{ _Lagenipora socialis_

{Orifice close to the upper end of the zooecium (unless crowned by an
{ ovicell). Front of the zooecium marked by transverse or
{ radiating furrows or lines. The very young zooecium may
38.{ possess a membranous area, which becomes roofed in by the
{ union of two lateral series of converging bars (Fig. 257) 39
{
{Characters not as above 40

{Furrows with uniserial rows of pores (often minute), which are rarely
{ irregular _Cribrilina_ (Fig. 257, A)
39.{No rows of pores. Distinct transverse lines or spaces and a
{ median longitudinal suture between the bars
{ _Membraniporella_ (Fig. 257, B)

{529}
{Zooecia arranged in regular series 41
40.{
{Zooecia irregularly[603] heaped together (cf. No. 30) _Cellepora_

{Primary orifice conspicuous; with a sinus, or with a peristome
{ extended or interrupted below, and sometimes simulating a
{ sinus 42
{
{Neither sinus[604] nor interrupted peristome 44
41.{
{Surface of the old zooecia much thickened, so that the secondary
{ orifice does not project beyond the most prominent parts of the
{ zooecium. Secondary orifice concealing the primary orifice,
{ wider above, enclosing a small avicularium below
{ _Porella_ (Fig. 255, B, C)

{Primary orifice with a sinus, but no tooth 43
{
42.{A prominent tooth projects into the orifice from its lower side.
{ Peristome interrupted or with a sinus. Surface of the old
{ zooecia not much thickened _Smittia_

{Orifice with a sinus and long spines. Peristome interrupted. Ovicell
{ with a wedge-shaped or linear longitudinal fissure. Avicularia
{ generally present, the avicularian zooecium conspicuous.
{ _Schizotheca_
{
43.{Orifice semicircular. Vibracula present, near the orifice.
{ _Mastigophora_ (Fig. 241, B)
{
{Orifice semicircular or subcircular. No vibracula; avicularia with
{ vibraculoid mandibles may occur _Schizoporella_ (Fig. 239, B)

{Zooecium with a median pore; _or_ completely tubular above 45
{
44.{Zooecium with no median pore. The orifice may be partially
{ surrounded by a collar-like development of the peristome,
{ but it is not completely tubular 49

{Orifice not tubular. A median pore _Microporella_ (Fig. 241, A)
45.{
{Orifice tubular 46

{Zooecia narrow or small 47
46.{
{Zooecia ovoid 48

{Orifice markedly tubular. Median pore conspicuous _Porina tubulosa_
{
47.{Colony very small. Zooecia irregularly arranged, with no median
{ pore _Celleporella_

{Zooecia very convex, with a granular surface; ovicells set far
{ back. Orifice wider than long _Mucronella microstoma_
{
48.{Young zooecia with stellate pores. A minute avicularium, or merely
{ a pore, on the upper and lower sides of the orifice in some
{ zooecia. _Anarthropora monodon_

{Front of zooecium with an elevated margin, enclosing an area 50
49.{
{Area not present 55

{Front wall wholly calcareous 51
50.{
{Front wall wholly or partly membranous 54

{Avicularian or vibracular zooecia replacing an ordinary {530}
{ zooecium, or at least situated between the zooecia 52
51.{
{Avicularia and vibracula absent, or if present not replacing a
{ zooecium 53

{Vibracula present. Colonies small. A pair of longitudinal slits
{ within the area _Setosella vulnerata_
52.{
{Very large avicularia present. Ovicell closed by a movable lid.
{ Orifice subcircular, with a minute lateral tooth on each side.
{ _Thalamoporella_[605] (_Steganoporella_) _smittii_

{Orifice semicircular, quite at the upper end of the zooecium; usually
{ with a knob on each side _Micropora coriacea_[606] (Fig. 256, C)
53.{
{A transverse chitinous plate lies immediately below the operculum.
{ A vibraculoid spine may occur _Megapora ringens_

{Area entirely membranous, usually bordered by spines.
{ _Membranipora_ (including _Electra_[607]) (Fig. 256, A)
54.{
{Membranous portion reduced to a small portion, which may be
{ variously lobed, enclosing the orifice.
{ _Membranipora_ (other species) (Fig. 256, B)

{Peristome present. No mucro 56
{
55.{Peristome absent; _or_ if present, with a mucro 57
{
{See also _Mucronella pavonella_, No. 28).

{Peristome collar-like, much raised below and at the sides of the
{ orifice, deficient above. No avicularia _Phylactella_
56.{
{Orifice large, longer than broad. Peristome not deficient above
{ the orifice _Lepralia_

{Wall of zooecium thin, shiny, and without pores 58
57.{
{Not agreeing with the characters given under No. 58 59

{A minute avicularium above the orifice, or where an ovicell is
{ present, situated at the summit of that structure. Zooecia not
{ quite contiguous. Mucro sometimes present.
58.{ _Chorizopora brongniartii_
{
{No avicularia. Ovicells on rudimentary zooecia, lying in a plane
{ superficial to that of the rest of the colony. Zooecia long.
{ _Schizoporella hyalina_

{A more or less distinct mucro or prominence beneath the orifice. 60
{
59.{Mucro rarely present. Orifice nearly always longer than broad, or
{ nearly circular, usually large, and slightly indented laterally.
{ _Lepralia_

{A tooth projects into the orifice from its lower side 61
60.{
{No tooth 62

{Colony glistening. Orifice much obscured by the mucro and by {531}
{ stout spines developed from the peristome. Tooth (concealed in
{ old zooecia) large, strongly curved to one side.
61.{ _Rhynchopora_ (_Rhynchozoon_[608]) _bispinosa_
{
{Tooth of the lower margin of the orifice symmetrical, sometimes
{ bifid. Avicularia may be present laterally, but are not
{ developed on the mucro _Mucronella_ (Fig. 255, A)

{Orifice at least half the width of the zooecium, bordered below by a
{ well-developed prominence or "umbo." Surface of the zooecium
62.{ strongly areolated round the margin _Umbonula_[609]
{
{Orifice considerably less than half the width of the zooecium.
{ _Schizoporella_ (Fig. 239, B)

CYCLOSTOMATA.

{Colony erect. Branches of two or one series of zooecia, divided at
{ intervals by chitinous joints. Ovicells pear-shaped.
63.{ _Crisia_ (Fig. 237)
{
{Colony erect, unjointed 69
{
{Colony in the main adherent; _or_ circular; _or_ lobed 64

{Colony more or less circular, discoidal or cup-shaped, sometimes
64.{ forming secondary colonies by marginal budding 65
{
{Colonies not circular 68

{Zooecia separated by calcified interspaces, which may contain large
{ pores, often difficult to distinguish from the orifices 66
65.{
{No large pores as above. Orifices not spiny. Zooecia nearly always
{ contiguous, except where an ovicell is developed 67

{Colony composed of one or more convex discs, bearing radial ridges,
{ each composed of many zooecia _Domopora_
{
66.{Colony encircled by a thin calcareous lamina, which gives rise to
{ new zooecia, its centre usually devoid of zooecia when adult,
{ and often bearing the orifice(s) of the ovicell. Zooecial
{ orifices often spiny. _Lichenopora_

{Zooecia with a long, tubular, free portion, in some cases curved
{ in a horizontal plane. Colony fan-shaped until a late stage.
{ _Tubulipora flabellaris_
67.{
{Tubular portion absent, or for the most part curved in a vertical
{ plane. Some of the orifices may be closed by a calcareous
{ plate. Colony circular or bluntly lobed _Diastopora_

{Zooecia in one or few series, forming a linear or branched {532}
{ colony, which is closely adherent, but may give rise to short
{ erect portions. Branches narrow, but often broadening at their
{ ends. Zooecia usually with a free upper end _Stomatopora_
{
68.{Colony broadly lobed, some of the zooecia in transverse or oblique
{ ridges composed of contiguous zooecia, arranged like a row of
{ organ-pipes _Idmonea serpens_
{
{Colony broadly lobed, or fan-shaped; zooecia in many series, which
{ are not arranged like organ-pipes _Tubulipora_

{Well branched. Orifices confined to one surface of the colony 70
69.{
{Not much branched 71

{Zooecia in transverse rows, their upper ends united in the manner
{ of a row of organ-pipes. Ovicell (when present) an inflation
70.{ of the front of the branch _Idmonea atlantica_
{
{Zooecia not in regular transverse rows. Ovicell (when present) large,
{ mostly on the back of the branch _Hornera_

{Branches cylindrical, their ends massive and raised into radial
{ ridges, which carry the orifices _Domopora stellata_
71.{
{Ends of zooecia tubular, arranged all round the branch.
{ _Entalophora_

CTENOSTOMATA.

{Colony entirely adherent, or forming thick, soft, erect lobes 73
72.{
{Colony erect, well-branched, dark and opaque, resembling seaweed.
{ Zooecia with a long tubular free portion _Anguinella palmata_

{Orifice large, with two distinct lips. A variable number of stout,
{ brown spines. Encrusting _Flustrella hispida_
{
{Orifice small, rounded, borne by a more or less distinct papilla.
73.{ Encrusting or erect. Zooecia crowded, rarely in single lines.
{ _Alcyonidium_
{
{Orifice small, rounded. Zooecia widely separated, connected by
{ narrow tubes _Arachnidium_

{Axis of colony erect, usually branched 75
74.{
{Axis creeping 79

{Zooecia in elongated clusters, which occur at intervals 76
75.{
{Zooecia not grouped; _or_ in irregular groups; _or_ in whorls 78

{Zooecia regularly biserial 77
76.{
{Zooecia long, less regularly arranged. Polypide with a gizzard.
{ _Bowerbankia_ (Fig. 238)

{Clusters of zooecia very regular, occurring immediately below a
{ bifurcation of the axis. Zooecium with a broad base, not
77.{ movable. _Amathia lendigera_
{
{Zooecia arranged like the pinnules of a leaf, with a constricted
{ base, and movable on the branch _Mimosella gracilis_

{Main stem zigzag. Branchlets delicate, many ending in sharp {533}
{ points. Zooecia small, ovoid _Vesicularia spinosa_
{
78.{Axis jointed. Zooecia small, in small clusters. Polypide without a
{ gizzard _Valkeria uva_, var. _cuscuta_
{
{Zooecia in whorls, attached to the axis by thread-like stalks,
{ much longer than themselves _Hippuraria egertoni_

{Zooecia pear-shaped, produced at the lower end into a distinct
{ stalk. Gizzard absent 80
79.{
{Zooecia not distinctly stalked, although sometimes constricted
{ at the base 81

{Stalk long. Zooecium movable on its stalk, compressed, with a
{ membranous area on one side. Twelve or more tentacles.
{ Usually found on Crustacea _Triticella_
{
80.{Stalk variable. Zooecium very transparent; orifice bilabiate. Ten
{ to sixteen tentacles _Farrella repens_
{
{Zooecium very small, much elongated and narrow. Eight tentacles.
{ _Valkeria tremula_
{(See also _Arachnidium_, No. 73).

{Zooecia short, minute, with a few short spines on each side of
81.{ its broadened base. Upper end tubular _Buskia nitens_
{
{Zooecia elongated 82

{Zooecia transparent 84
82.{
{Zooecia brown, often quite opaque 83

{Zooecia large (about 1/16 inch long), distant, constricted at the
{ base, bearing scattered bristles. Usually found on Crabs or
83.{ Hydroids. _Avenella fusca_
{
{Zooecia tall, cylindrical, not constricted at the base.
{ _Cylindroecium_

{Zooecia minute. Axis dilating at intervals into swellings, from
{ which new zooecia originate. These may give rise to new
84.{ stolons,or directly to new zooecia. No gizzard. Found in
{ brackish or fresh water _Victorella pavida_
{
{Axis not dilated, as above 85

{Zooecia small, in small groups. No gizzard _Valkeria uva_
85.{
{Zooecia long, scattered or in groups. Gizzard present.
{ _Bowerbankia_ (creeping forms)

It is highly probable that the Ctenostome genus _Hypophorella_[610] will before long be added to the British Fauna. The animal consists of delicate stolons, which give off small zooecia at intervals; and it is known to excavate passages in the substance of the tubes of certain Polychaet worms (_Chaetopterus_ and _Lanice_).

{534}ADDENDUM TO CHAETOGNATHA

Since the Chapter on the Chaetognatha was printed the following list[611] of "The Known Chaetognaths of American Waters" has appeared:—

1. _Sagitta elegans_ Verr. This species resembles _S. bipunctata_ (_vide_
pp. 191 and 193), but differs in size, in the relative proportions of
caudal and body segments, and in the presence of diverticula from the
intestine.

2. _Sagitta flaccida_ Con. This species resembles _S. hexaptera_ (_vide_
p. 193); it is, however, smaller (length, 1.3-1.8 cm.) and has more
spines (anterior, 7-8, posterior, 10-12), and its tail segment is
relatively smaller.

3. _Sagitta tenuis_ Con. Length, 5.25 mm.; hooks, 7-8; anterior spines,
4-5; posterior spines, 7-10.

4. _Sagitta hispida_[612] Con. Length, 7-11 mm.; hooks, 8-9; anterior
spines, 4-5; posterior spines, 8-15; tail segment one-third body length;
intestine with two diverticula; sensory hairs very numerous.

5. _Sagitta hexaptera_ (_vide_ p. 193).

6. _Krohnia hamata_ (_vide_ p. 194).

7. _Spadella maxima_ Con. Length, 5.2 cm.; hooks, 6; anterior spines,
3-5; posterior spines, 5-7; epidermal thickenings round the neck.

8. _Spadella draco_ (_vide_ p. 194).

9. _Spadella schizoptera_[612] Con. An opaque, yellowish-brown species
living among algae. Length, 4 mm.; hooks, 8; anterior spines, 4-6;
posterior spines wanting. Caudal segment occupies one-half the body
length.

Professor Verrill states that the name _S. gracilis_ (_vide_ p. 191) was due to a clerical error, the species really referred to being _S. elegans._

A. E. S.

{535}CHAPTER INDEX

Every reference is to the page: words in italics are names of genera or
species; figures in italics indicate that the reference relates to
systematic position; figures in thick type refer to an illustration; f. =
and in following page or pages; n. = note.

_Acanella_, as host, 298
_Acanthobdella_, 395
Acanthocephala, 123, 124, 174 f.;
embryology, 179;
classification, 181
_Acanthocotyle_, _73_
Acanthodrilidae, 357, 362, 381, 383, _384_
_Acanthodrilus_, 356, 363, 366, 372, 382, _384_;
chaetae, 350
_Acanthozoon_, 20
Accessory gut, of Polychaeta, 305
_Aceros_, _19_
Achaeta, 445
_Acholoe_, 297
Aciculum, 247; fossil, 302
_Acmostoma_, _50_
Acoela, 42;
occurrence and habits, 43;
reproduction, 47;
classification, 49
Acotylea, 16 f., 17, 18
_Acrorhynchus_, _49_;
occurrence, 44
Actinotrocha larva, 458
_Actinurus_, 201, _222_
_Acyclus_, _221_
Adaptation, of Trematodes, 52, 62;
of Cestodes, 74;
of Nematodes, 161
Adherent, 523
_Adineta_, 204, _222_, 227
Adventitious avicularia, 482
_Aeolosoma_, 349, 353, 354, 360, 370, 374, _375_
_Aetea_, _518_, 525
Agassiz, on Syllidae, 280
_Alaurina claparedii_, _49_
_Albertia_, 204, 210, 213, _224_, 227
_Alciope_, _315_
Alciopids (Alciopina), _314_;
head, 263;
parapodium, 265;
habit, 291;
light-organs, 294
_Alciopina parasitica_, 298
_Alcyonella_, 494, 505, _518_
Alcyonellea, _518_
_Alcyonidium_, 477, 480, 492, _518_, 532;
structure of zooecium, 469;
reproduction, 507, 508;
larva, 510, 511
Alimentary canal—see Digestive System
_Alitta_, 317
_Allantonema_, 131, _150_, 151, 161
Allman, on Polyzoa, 474, 475
Alloeocoela, 43; habits, 46;
reproduction, 47;
classification, 50
Alloiogenesis, 66 n.
_Allolobophora_, 351, 367, 369, 371, 386, 389, _390_ f.;
cocoons, 365
_Allostoma pallidum_, _50_
_Alluroides_, _379_
_Allurus_, 351, 366, 370, 389;
cocoons, 365
_Alma_, 352 f., 387
Alternation of generations, 66, 81, 281
_Amathia_, 481, _518_, 532
Ammocharidae, _258_, _325_
_Ammotrypane_, 273, _331_;
intestine, 271
_Ampharete_, _330_
Ampharetidae, _258_, _330_
Amphibia, Trematodes of, 55, 62, 71, 72;
Nematodes of, 163
_Amphichaeta_, _377_
_Amphicoerus_, _49_
_Amphicora_, 339
_Amphicorine_, gill, 261
Amphicorinidae, _258_, _339_
_Amphicteis_, _330_
Amphictenidae, _258_, _330_
_Amphiglena_, 273, _339_
_Amphileptus_, 235
_Amphilina_, _91_
_Amphinome_, eye of, 255;
_A. smaragdina_, colour, 293
Amphinomidae, _258_, _318_;
shape, 259;
caruncle, 260, 273 n.;
head, 262, 263;
parapodium, 264;
cirri, 265;
chaetae, 267, 267;
in _Lepas_, 297
_Amphiporus_, 102, 114;
British species, _110_
_Amphiptyches_, 77
Amphistomatidae, _73_ {536}
_Amphistomum_, 71, _73_;
_A. hominis_, 63
_Amphitrite_, 327, _328_;
gill, 329
_Ampullaria_, _Temnocephala_ with, 53
_Anachaeta_, 350, _376_, 395
Anal, cirri, 259;
funnel, 259, 332, 333;
vesicles, 358, 436
Anangian worms, 253
_Anarthropora_, 529
_Ancylostomum_, 143, 163
Andrews, on _Sipunculus_, 417, 426
_Angiostomum_, 134
Angler-fish, Trematodes of, 62, 72
_Anguillula aceti_, 125, _154_;
_A. tritici_, 125;
_A. diplogaster_, 155
Anguillulidae, 137, _154_
_Anguinella_, 532
_Annadrilus_, _386_
Annelida, 241
_Anocelis_, _42_
Anonymidae, _19_
_Anonymus_, 16, 18, _19_, 20;
penes, 27
Anopla, 109
_Anoplocephala_, _91_;
characters, 90:
_A. mamillana_, 90;
_A. perfoliata_, life-history, 83;
specific characters, 90:
_A. plicata_, specific characters, 90
_Anoplodiscus_, _73_
_Anoplodium_, _50_;
_A. parasiticum_, occurrence, 45
_Antaeus_, 388
_Antedon_, as host, 342
Antenna, of Rotifers, 215
_Anthobothrium_, 76 n., _91_
_Anthocotyle_, _73_
_Antinoë_, 298
_Antipathes_, as host, 298
_Anuraea_, _225_, 226
Anuraeidae, 201, 205, _225_, 226
A'oon, an edible worm, 297
Apel, on Priapuloidea, 433
Aperture, of zooecium, 468, 517, 523, 524
Aphaneura, 353, _374_
_Aphanostoma_, _49_
Aphanostomatidae, _49_
_Aphelenchus_, 131, _155_, 157
_Aphrodite_, _312_;
shape, 258;
head, 260;
peristomium, 263;
chaetae, 268;
felting, 312;
intestine, 271;
genital cells, 273;
colour, 291:
_A. aculeata_, 312;
distribution, 299;
_A. echidna_, 299
Aphroditidae, _258_, _309_;
frontal ridge, 260;
parapodium, 264;
elytra, 266, 309;
chaetae, 266
Apical plate, of Trochosphere, 245
Apodina, _235_
_Apodoides_, _225_
_Apogon_, _Scolex polymorphus_ in, 77
Apsilidae, 201, 203, 214, 220, _221_
_Apsilus_, 201, 212, 213, 214, _221_
_Arabellites_, 302
_Arachnidium_, 532
Archiannelida, _241_;
anatomy, 243 f.;
nerve cords, 255;
development, 243, 245
_Archigetes_, 5, 74, 76, _91_;
significance of, 77
Area, of zooecium, 523, 524
_Arenicola_, _333_;
perienteric sinus, 252;
nephridium, 253, 254, 269;
prostomium, 259;
body, 259;
head, 264;
gill, 265;
chaetae, 266 f.;
genital organs, 273;
otocyst, 273;
burrows, 285;
pigment, 291;
colour, 293;
_A. marina_, 333;
habits, 301;
in brackish water, 284;
as bait, 297;
eggs, 314
Arenicolidae, _258_, _333_
_Argilophilus_, 372
Arhynchidae, _185_
_Arhynchus hemignathi_, 181, _185_
_Aricia_, otocyst, 273;
eggs, 275
Ariciidae, _258_, _321_;
gill, 265
Aristotle, on Earthworms, 347
Armata, 445, 446
Arthropoda, absence of cilia in, 124
Articulata, _517_, _518_
Ascaridae, 131, _138_, 163
_Ascaris_, _139_, 163;
_A. acus_, 130;
_A. alata_, 140;
_A. depressa_, 141;
_A. ferox_, 141;
_A. incurva_, 141;
_A. leptoptera_, 141;
_A. lumbricoides_, 125, 134, 135, 139, 163;
_A. megalocephala_, 125, 127, 128, 131, 136, 140, 163;
_A. mucronata_, 141;
_A. mystax_, 125, 130, 140;
_A. nigrovenosa_, 155;
_A. rubicunda_, 141;
_A. suillae_, _139_;
_A. sulcata_, 141;
_A. transfuga_, 125, 126, 141
_Ascodictyon_, 521 n.
_Ascomorpha_, _223_
_Ascopodaria_, 488 n.
_Asellus_, Rotifers attached to, 227
Asexual reproduction, in Triclads, 40;
in Rhabdocoels, 44;
in Cestodes, 80;
in _Trichoplax_ and _Salinella_, 96;
in Polychaeta, 278 f., 279, 280, 282, 340;
in Oligochaeta, 374, 375, 377;
in Polyzoa, 496, 514
Aspidobothridae, _73_
_Aspidocotyle_, _73_
Aspidocotylea, _73_
_Aspidogaster_, 63, _73_
_Aspidosiphon_, 421, 423, 424, _425_, 428;
commensalism of, 429
_Asplanchna_, 200, 205, 210, 213, 215 n., _223_, 226
Asplanchnaceae, 203, 212, _220_, _222_
Asplanchnidae, 200, 201, 203, 205, 211, 212, 216, _223_, 226, 230
_Asplanchnopus_, 201, 211, 222, _223_, 226, 230
Ass, parasites of, 140
Association, of Rhabdocoels with Lamellibranchs and Sea-urchins, 45;
of _Monotus fuscus_ with littoral animals, 46;
significance, in Turbellaria, 51—see also Commensal and Parasitic
Asteroids, as hosts, 341 {537}
_Asterope_, _315_
_Astropecten_, as host, 297, 309
Atokous phase, 277 n.
_Atractonema_, 131, _150_, 152, 153
Atrium (genital), in _Planaria_, 38, 39;
in Oligochaeta, 361, 378
_Atrochus_, 201, 213, 214, _221_
Auditory organs, of Turbellaria, 26;
of Hoplonemertea, 106, 110;
of Nematoda, 128;
of Polychaeta, 273
_Aulastomum_, 393, 399, 403
Auricles, of Rotifers, 205
_Autolytus_, _308_;
eye, 255;
denticles, 270;
brood-sac, 275, 276;
reproduction, 278, 279;
sexual dimorphism, 281;
_A. ebiensis_, eggs, 276
_Automolos_, British species, _50_
_Avenella_, 533
Avicularian zooecium, 482, 524
Avicularium, 466, 467, 468, 482 f., 482, 516, 517, 522 f., 524;
adventitious, 482;
vicarious, 482;
vibraculoid, 484, 485;
structure, 483;
movements, 485;
function, 486
_Axine_, 56, _73_
_Axiothea_, _332_, 333

Baely, on human parasites, 139
Baird, on Oligochaeta, 382
Bait, Polychaeta as, 297
Baker, on Rotifers, 197, 207; on Polyzoa,
496 n.
_Balanoglossus_, affinities of Nemertinea with, 120
_Balatro_, 204, 212, _224_, 227
Balfour, on Trochosphere, 229
_Barentsia_, 488 n.
Barrois, on Polyzoa, 509
Basement-membrane, of _Leptoplana_, 11, 12;
of Nemertines, 102, 103, 110 f.
Bathymetrical distribution, of Polychaeta, 300
_Bdellodrilus_, _376_
Bdelloida, 201, 203 f., 211, 213, 215, 216, _222_, 227
Bdellouridae, 32, _42_
_Beania_, _518_, 525
Beddard, on _Tetrastemma aquarium dulcium_, 118;
on Oligochaeta, 347 f.;
on Leeches, 392 f.
Bedwell, on Rotifers, 198
Beneden, van, on Cestodes, 76;
on Nematodes, 162;
on _Phoronis_, 450
Benham, on a fresh-water _Tetrastemma_, 118;
on Archiannelida, 241 f.;
on Polychaeta, 245 f.;
on Myzostomaria, 341 f.;
on Oligochaeta, 357, 373, 382;
on _Phoronis_, 452 f.
_Benhamia_, _383_ f.
_Bicellaria_, 481, _518_, 526, 527
Bilfinger, on Rotifers, 212
_Bilharzia_, 4, _73_;
_B. crassa_, 70;
_B. haematobia_, 63, 68 f., 69
_Bimastos_, _389_
Bipaliidae, 35, _42_
_Bipalium_, 33, 34, _42_, 408
Birds, Trematodes of, 62, 63, 64, 72;
Cestodes of, 77 f., 84, 85;
Nematodes of, 144, 149, 163;
_Gordius_ of, 173;
Acanthocephala of, 184, 185
Bisexual, Turbellaria, 44;
Trematodes, 70 f.
Bladder, of Rotifers, 214
Bladder-worms, 5, 79 f., 89
Blanchard, on Cestoda, 91;
on Hirudinea, 392 f., 405, 408
Blastomeres, of egg of _Distomum_, 65
Blood, of Nemertinea, 108;
of _Polygordius_, 244;
of Chaetopoda, 252;
of Chlorhaemidae, 252, 334;
of _Magelona_, 252, 325;
of Sabelliformia, 252, 337
Blood-corpuscles, in Chaetopoda, 252
Body-cavity (including Coelom), of Nematoda, 130;
of _Gordius_, 166;
of Acanthocephala, 175, 178;
of Chaetognatha, 187;
of Archiannelids, 243, 244;
of Polychaeta, 249;
of _Myzostoma_, 343;
of Oligochaeta, 355;
of Leeches, 397;
of Gephyrea, 416;
of _Phoronis_, 454, 462;
of Polyzoa, 468, 488, 495
Body-wall, of Nemertinea, 102, 103;
of Nematodes, 125;
of Gordiidae, 165;
of Acanthocephala, 175;
of Chaetognatha, 187;
of Rotifers, 205;
of _Nereis_, 249;
of Oligochaeta, 349;
of Gephyrea, 414, 436;
of _Phoronis_, 454;
of Polyzoa, 470, 495, 500
Bohadsch, on Gephyrea, 411
_Bohemilla_, _377_;
chaeta, 350
Bonellein, 435, 292
_Bonellia_, 411, 434, _442_;
anatomy, 434 f., 435;
male, 438;
development, 439;
habits of, 442;
as host, 297
Bonnet, on Oligochaeta, 348, 379
Boring Worms, 286, 287
Borlase, on _Lineus marinus_, 99
_Borlasia elizabethae_, _111_, 114
Bothriocephalidae, _91_
Bothriocephalinae, _91_
_Bothriocephalus_, _91_;
_B. cordatus_, 81, 91;
_B. cristatus_, 81, 91;
_B. latus_, in man, 81, 91;
life-history, 84;
reproductive organs, 87 f.;
larva, 87;
_B. mansoni_ (= _B. liguloides_), 81, 91
_Bothriocerca_, 226
_Bothrioneuron_, _379_
_Bothrioplana_, 46, _50_
Bothrioplanidae, 42, 46, _50_
_Bothromesostoma personatum_, _49_
Bourne, on Oligochaeta, 352, 373, 377 n., 380;
on Leeches, 400
Bouvier, on commensal Gephyrea, 429
_Bowerbankia_, 470, 480, 481, 492, 500, _518_, 532, 533; {538}
larva, 511, 513;
budding, 514
Brachionidae, _225_
_Brachionus_, 200, 201, 204, 218, _225_, 226, 227
_Brachydrilus_, 357
Brackish water, Rotifers, 226;
Polychaeta, 284;
Polyzoa, 492
_Bradynema_, _150_, 151, 160
Braem, on statoblasts, 503 f.
Brain—see Nervous System
_Branchellion_, 393, 395, 397, 401, _406_
Branchial crown, 336;
regeneration of, 283
_Branchiobdella_, _376_
_Branchiomma_, _337_;
gills, 261;
eyes, 272;
_B. vigilans_ on _Aphrodite_, 299
_Branchiura_, 352, 361, 367, _378_ f.;
transverse section, 353
Braun, on Platyhelminthes, etc., 6 n., 55 n., 62, 94
_Brettia_, 525, 527
Bristles = Chaetae, _q.v._
Bristle-worms, 241
British, Polycladida, 19;
Tricladida, 42;
Rhabdocoelida, 49;
Nemertinea, 100, 110 f.;
Polychaeta, 306 f.;
Earthworms, 390;
Leeches, 393;
Gephyrea, 449;
Polyzoa, 488 n., 505, 523 f.
Brood-pouch, of _Spirorbis_, 261, 276, 341;
of _Salmacina_, 276;
of Entoprocta, 487, 507
Brood-sac, of _Autolytus_, 275;
of _Myrianida_, 280
Brown body, in Polyzoa, 468, 471 f., 472, 489, 496, 510, 514
Brown tubes (nephridia), of Sipunculoidea, 415, 417, 423, 425;
of Echiuroidea, 435, 437, 439, 441;
of Epithetosomatoidea, 445;
used as generative ducts, 418, 438;
absent in Priapuloidea, 430
Bryozoa, 475
Buccal region, in Polychaeta, 249, 250, 269;
of _Nereis diversicolor_, 248;
of _N. cultrifera_, 316
Buchanan, on marine muds, 423
_Buchholzia_, 359
Budding, in Syllidae, 279, 283 (see also Gemmation);
in Polyzoa, 467, 514 (see also Polypide-bud)
_Bugula_, 467, 468, 477, 481, 515, 517, _518_, 519, 526;
avicularia, 483, 485;
larva, 511
Bunge, on respiration in Nematoda, 130
Bürger, on Nemertinea, 109, 112;
on _Nectonema_, 168;
on Hirudinea, 397, 403
Burrows, of Polychaeta, 285, 304;
of _Cirratulus_, 286;
of _Nereis_, 286, 316, 317;
of _Arenicola_, 333;
fossil, 302;
of Earthworms, 368;
of _Sipunculus_, 426
Bursa seminalis, in Rhabdocoels, 48
Busk, on Polyzoa, 465 n., 475, 487, 519
_Buskia_, 533
Bütschli, on Nematoda, 137
_Byrsophlebs_, occurrence, 44;
British species, _49_

_Caberea_, 487, _518_, 526;
vibracula, 486, 517
Caecum, in Polyzoa, 499
_Calathus_, host of _Gordius_, 172
Calceostominae, _73_
_Calceostomum_, _73_
Caldwell, on _Phoronis_, 454, 456, 461
_Calicotyle_, _73_
_Callidina_, 201, 202, 204, 218, 219, _222_, 225, 227, 230
_Calliobothrium_, 76 n., _91_;
larva, 77
Calotte, of Dicyemids, 93
Calyx, 488
Camerano, on development of _Gordius_, 170
_Capitella_, _331_;
peristomium, 263;
special chaetae, 267, 268;
habitat, 286;
colour, 291;
_O. capitata_, distribution, 299
Capitellidae, _258_, _331_, 373
Capitelliformia, _258_, _305_;
guanin in, 253;
body, 259;
buccal region, 269;
siphon, 272;
ciliated organs, 272, 273;
genital organs, 273
_Carabus_, host of _Gordius_, 172
_Carinella_, 112;
British species, _112_
Carinellidae, side organs of, 107
Caruncle, of Amphinomidae, 260, 273 n., 318
_Caryophyllaeus_, _91_;
_C. mutabilis_, 77
_Castalia_, _308_;
distribution of, 300
Castings, of Polychaeta, 285;
fossil, 302;
of _Arenicola_, 333
_Castrada_, 44, _49_
Cat, parasites of, 80, 125, 130, 140, 143, 144, 145
_Catenicella_, _518_, 519
_Catenula_, _49_
_Cathypna_, _225_
Cathypnidae, _225_
_Cellaria_, 479, 515, _518_, 519, 526;
zooecia and avicularium, 482
_Cellepora_, _518_, 527, 528, 529;
avicularia, 483, 517
_Celleporella_, 529
_Cellularia_, _518_, 527
Cellularina, _518_
Cement-glands, of Rotifers, 205
Cephalic slits, of Nemertinea, 101, 104, 107, 111, 112
Cephalisation, in Polychaeta, 263;
in Oligochaeta, 377
_Cephalodiscus_, 461 f.
Cephalopods, parasites of, 78, 92;
list of, containing Dicyemids, 94
_Cephalosiphon_, 205, _221_
_Cephalothrix_, _112
Cercaria_, 13, 65, 67, 71 f.; {539}
_C. macrocerca_, 72;
_C. cystophora_, 72
_Cercyra_, 42
Cerebral organ, of Nemertinea, 107;
of Gephyrea, 417
_Cerebratulus_, 101, 111, 114;
British species, _111_
Cerfontaine, on Earthworms, 349, 350
Cestoda, characters of the group, 5, 74;
nature of, 76 f.;
occurrence, 77-82;
life-histories, 83;
structure and development, 84-89;
synoptic table of, 89 f.;
classification, 91
Cestodariidae (= Monozoa), _91_
_Cestoplana_, 17, 18, _19_
Cestoplanidae, _19_
Chaetae, 241;
of Polychaeta, 266, 267;
provisional, 274;
of _Nereis_, 246, 247;
of Heteronereid, 276, 277;
jointed, 246;
natatory, in sexual Syllid, 278, 307;
iridescent, 268, 291, 312;
palmate, of _Coabangia_, 339 n.;
colour, 291;
genital, of _Capitella_, 331;
of _Sternaspis_, 336;
special, of _Polydora_, 261, 267;
of _Chaetopterus_, 267, 324;
of _Myzostoma_, 342;
of Oligochaeta, 347, 350, 351, 352;
penial, 362;
of Microdrili, 375 f.;
of Megadrili, 381 f.;
of Lumbricidae, 389, 390;
of Leeches, 395, 396;
(= hooks), of Echiuroid Gephyrea, 434, 435, 438, 440 f., 446
Chaetifera, 445, 446
_Chaetobranchus_, 352
_Chaetogaster_, 356, 377, 401
Chaetognatha, 186 f., 534;
anatomy, 186;
development, 189;
habits, 189;
classification, 191;
key to, 193;
American species, 534
_Chaetonotus_, 232, _235_
Chaetopoda, 241 f.;
as food for Nemertinea, 115
Chaetopteridae, 258, _323_
_Chaetopterus_, 304 n., _323_;
anatomy, 323 f.;
special chaetae, 267;
larva, 274, 325;
pigment, 292;
phosphorescence, 295, 296;
commensals of, 298, 478, 533;
_Ch. variopedatus_, 324
_Chaetosoma_, 158
Chaetosomatidae, _158_
Chaetosyllis, form of head, 278
_Chaetozone_, _326_;
uncini, 268
_Chaetura_, _235_
Chalk, Serpulids of, 301
Charles, on male guinea-worm, 148
Cheilostomata, _477_, 506, _518_, 519, 525, 526 f.;
occurrence, 478;
external characters (see also Avicularium and Vibraculum), 481;
ovicells, 507;
reproduction, 507 f.;
larva, 511;
fossil, 521
Chiaje, Delle, on Gephyrea, 411
Chickoff, on Triclads, 41
_Chironomus_, host of _Gordius_, 172
Chitin, 249, 267;
in coelomic corpuscles, 252
_Chloeia_, colour, 291
Chlorhaemidae, _258_, 305, _334_, 336;
chlorocruorin in, 252;
head, 260, 262, 264;
palps, 260;
tentacles, 262
Chlorocruorin, 252, 334;
colour due to, 291
_Chone_, _338_
_Chorizopora_, 530
Cilia, 3;
of _Leptoplana_, 10, 11, 12, 15;
of Polyclads, 23, 25, 26;
of Müller's larva, 29;
of Land Planarians, 33;
of _Planaria lactea_, 35;
of _Temnocephala_, 53;
of Trematode-larvae, 3, 59, 60, 65;
of Cestode-larvae, 87;
absent in certain groups, 124, 396;
of Rotifers, 202 f.;
of Archiannelida, 243, 244;
of Echiuroidea, 434;
of _Phoronis_, 453;
of Polyzoa, 467, 470
Ciliated, lappets, of _Pterosyllis_, 273 n.;
pits, of _Polygordius_, 244;
pits (= nuchal organs), of Polychaeta, 272 f.;
organs, of Capitelliformia, 305
Cingulum, in Rotifers, 202
Cirratulidae, _258_, _325_;
gill, 265;
tentacular filaments, 304 n.
_Cirratulus_, _326_;
burrows, 286;
pigment, 292;
colour, 293;
viviparous, 276;
_C. tentaculatus_, 326
Cirri, of _Nereis_, 246;
of Polychaeta, 265;
of _Myzostoma_, 342;
anal, 259;
nuchal, of Eunicidae, 318;
peristomial, of _Nereis_, 248;
nerves to, 254;
of Polychaeta, 263
_Cladocora_, with _Myxicola_, 294
Claparède, on Heteronereis, 276, 277;
on Earthworms, 347, 355, 356
Claus, on Nematoda, 138;
on Seisonaceae, 225 n.
_Clepsine_—see _Glossiphonia_
_Clitellio_, 366, 378
_Cloeosiphon_, 424, _425_, 429
Clover sickness, 155
_Clymene_, _333_;
_C. ebiensis_, tube of, 287
Clymenidae—see Maldanidae
_Coabangia_, 284, _339_ n.
Cobb, on Nematoda, 131 n., 138
Cobbold, on Nematoda, 140
_Cobitis_, host of _Gordius_, 173
_Cochleare_, _225_
Cocoons, of Triclads, 40;
of Oligochaeta, 364, 365;
of Leeches, 404
Coelom—see Body-cavity
Coelomic fluid, of Polychaeta, 252;
as cause of colour, 291
_Coelopus_, _225_
Cohn, on Rotifers, 198
Collar, peristomial, of Sabellidae, 336;
of Gephyrea, 421;
of Ctenostomata, 470, 477, 480, 481
Colonial nervous system, 471
Colony, of _Myrianida_, 281; {540}
of _Syllis ramosa_, 282;
of Polyzoa, 466
Colour of Polyclads, 20;
of Land Planarians, 33;
of Nemertinea, 102;
of Polychaeta, 291, 314, 340
Coluridae, 207, _225_
_Colurus_, _225_, 226
_Comatula_, as host, 342
Commensal, Polychaeta, 297 f., 323, 325;
Gephyrea, 428, 429;
Polyzoa, 489
Conn, on development of Gephyrea, 419 n., 441, 444, 447
_Conoceros_, _19_
_Conochilus_, 202, 203, 205, 215, _221_, 226
_Conocyema_, hosts of, 94
_Convoluta_, 45;
British species, 43, _49_;
_C. henseni_, pelagic habit, 43;
_C. roscoffensis_, assimilating tissue, 43
Copepoda, on Polychaeta, 299
_Copeus_, 215, _224_
Coral reefs, Polychaeta in, 293
_Corallina_ (= Coralline Alga), 14, 488, 516
Coralline, 465
Coralline Crag, 465, 521
_Corallobothrium_, _91_
_Corethra_, host of _Gordius_, 172
Cori, on _Phoronis_, 451 f.
_Cornulites_, 302
Cotylea, 16 f., 17, 18
_Cotylogaster_, _73_
_Cotyloplana_, 35
_Crateromorpha_, as host, 282
Crayfish, _Temnocephala_ associated with, 53
Creeper, 317
_Crepina_, 450
Cretaceous, Polyzoa, 520, 521
_Cribrilina_, _518_, 524, 528
Crinoids, as hosts, 341
_Criodrilus_, 358, 366, _386_
_Crisia_, 471, 478, 479, 480, 507, _518_, 531
Crisiidae, _517_
Crisp, on Parasites, 164
_Cristatella_, 494 f., 495, 499, 501, 503-505, 512, _518_;
attacked by Planarians, 486;
movements, 494, 496, 498;
fission, 496, 506;
statoblast, 502, 503;
larva, 512
_Crossopodia_, 302
Crotchets, 266, 267, 305, 322
Crustacea, parasites of, 174, 179, 182
_Cryptocelis_, _19_, 24
Cryptocephala, _258_, _303_, _305_;
vascular system, 252;
prostomium, 259;
tentacles, 263;
eyes, 272;
food, 296
Cryptodrilidae, 357, 362, 373, _382_
_Cryptodrilus_, 372, _382_ f.
_Ctenodrilus_, 373
Ctenophores, as hosts, 298
Ctenostomata, 470, _477_, 479, 480, _518_, 532;
occurrence, 478;
in fresh water, 492;
external characters, 480;
reproduction, 507;
larva, 511;
relation to Phylactolaemata, 493, 502 f.;
fossil, 521 n.
_Cucullanus_, 136, _142_, 163;
_C. elegans_, 143, 161
_Cucumaria_, as host, 298
Cuénot, on Gephyrea, 416 n.
Cuticle, of Nemathelminthes, 125, 165, 175;
of Rotifera, etc., 205, 233, 236;
of Polyzoa, 470—see also Epidermis
Cuvier, on Oligochaeta, 352;
on Gephyrea, 411
_Cyclatella_, _489_
_Cyclicobdella_, 392
_Cycloporus_, _19_, 22, 24
_Cyclops_, parasites of, 143, 148, 161
Cyclorhagae, 238
Cyclostomata, _477_, 479, 506, _517_, _518_, 525, 531;
occurrence, 478;
external characters, 480;
ovicells, 507;
reproduction, 507, 511;
larva, 511; fossil, 520, 521
_Cydippe_, as host, 298
_Cylindroecium_, 533
_Cylindrostoma_, 46;
British species, _50_
Cyphonautes, 509, 510, 512, 520
_Cyprina_, _Malacobdella_ found on, 119
_Cyrtonia_, _224_
Cyst, of Land-Planarians, 33;
of _Myzostoma_, 342, 343, 344;
(capsules), of _Aeolosoma_, 370, 375
_Cystibranchus_, 395, _406_
Cysticercoid-larva, 83, 85, 88
_Cysticercus_-larva, 79, 80;
list of, 83;
_C. cellulosae_, 79, 80;
_C. pisiformis_, development, 81, 85, 89
Cysticolous, Myzostomaria, 344
Cystoidotaeninae, _91_
Cystotaeninae, _91_

_Dactylogyrus_, _73_
Dalyell, on habits of Turbellaria, 6, 10, 20;
on regeneration in Polychaeta, 283;
on tubes of Polychaeta, 287;
on Hirudinea, 405 n.;
on larvae of _Flustra_, 466;
on _Cristatella_, 496
Danielssen and Koren, on Gephyrea, 442, 444
_Daphnia_, Rotifers attached to, 227
_Dapidia_, _225_
Darwin, on Earthworms, 354, 359, 368
_Dasybranchus_, _331_;
gill, 268
_Dasychone_, _338_;
gills, 261;
eyes, 272;
regeneration, 283
_Dasydetes_, 232, _235_
Davaine, on Nematoda, 140, 145
_Davainea_, _91_;
_D. friedbergeri_, 84;
_D. madagascariensis_, 80, 84;
_D. proglottina_, life-history, 84
Davenport, on _Urnatella_, 491
Davis, on Rotifers, 227
Deep-sea, Polychaeta, 300;
Polyzoa, 478
_Deinodrilus_, 351, _384_
_Delagia_, 478 n.
_Dendrobaena_, _382_ {541}
_Dendrocoelum_, 30, 35, 39
_Dendrostoma_, 422, _425_, 428
Dendy, on Land Planarians, 33, 34, 38
Denticles, 248, 250, 316, 522
_Dero_, 352, _377_
_Derostoma_, 44, _50_
_Desmogaster_, _380_
Desmoscolecidae, 159
_Desmoscolex_, 159, 258
Desor, on Nemertine development, 99;
Type of, larva, 113
Development, of Polyclads, 28;
of Nemertinea, 99, 113;
of Nematoda, 135;
of _Gordius_, 171;
of Acanthocephala, 179;
of Chaetognatha, 189;
of Rotifers, 218;
of Archiannelida, 243, 245;
of Polychaeta, 274 f.;
of Oligochaeta, 365;
of Leeches, 399;
of Gephyrea, 419, 432, 439, 447;
of _Phoronis_, 458;
of Polyzoa, 506, 509—see also Life-history and Larva
_Diachaeta_, 366
Diaphragm, of _Nereis_ introvert, 250, 251;
of Terebellidae, 304, 327;
of Polyzoa, 469, 470, 500, 508
_Diaschiza_, _225_, 226
_Diastopora_, _518_, 531
_Dichogaster_, 362, _383_
_Diclidophora_, _73_
_Dicotylus_, 32, 35, 36, _42_
_Dicranotaenia_, _91_;
_D. coronula_, life-history, 84
_Dicyema_, 93;
vermiform larva of, 92;
hosts of, 94
_Dicyemennea_, 93, 93;
hosts of, 94
Dicyemidae, 92 f.
_Didymogaster_, _383_
_Didymozoon_, _73_;
_D. thynni_ (= _Monostomum bipartitum_), 71
Didymozoontidae, _73_
_Digaster_, 358, 359, _382_ f.
Digenea (Digenetic Trematodes), 5, 52, 62, _73_;
occurrence and habits, 62;
life-histories, 63 f., 71 f.
Digestive system, of _Leptoplana_, 11, 12;
of Polyclads, 24;
of Triclads, 37, 39;
of Rhabdocoelida, 42 f.;
of _Temnocephala_, 53, 54;
of _Polystomum_, 57;
of _Distomum_, 62;
absence of, in Cestodes, 74;
of Nemertinea, 103, 103, 104;
of Nematoda, 130;
of Gordiidae, 166, 169;
of Chaetognatha, 187;
of Rotifers, etc., 209, 233, 237;
of Archiannelida, 243;
of Polychaeta, 249, 269;
of Oligochaeta, 358;
of Hirudinea, 396;
of Gephyrea, 414;
of _Phoronis_, 454;
of Polyzoa, 468, 469, 487
_Digitibranchus_, 353
_Diglena_, 212, 217, _224_, 226
Digonopora, 16
Dimorphism, in _Polystomum_, 59;
sexual, of Trematodes, 70;
of Orthonectida, 95;
of _Dinophilus_, 243;
of Polychaeta, 276, 279 f.;
of Gephyrea, 438
Dinocharididae, _225_
_Dinocharis_, _225_
_Dinophilus_, 242;
_D. taeniatus_, 242;
_D. gyrociliatus_, sexual dimorphism, 243
_Dinops_, _223_
_Diopatra_, gill, 318
Diphyllinae, _91_
_Diplax_, _225_
_Diplectanum_, _73_
_Diplobothrium_, _73_
_Diplocardia_, _385_
_Diplodiscus_, _73_;
_D._ (_Amphistomum_) _subclavatum_, life-history, 71
_Diplogaster_, _154_
_Diplois_, _225_
_Diplostomum_, _73_
_Diplozoon_, 55, 60, _73_;
life-history, 60, 61;
reproductive organs, 60
_Diporochaeta_, _381_
_Diporpa_, 60, 61
_Diporula_, 528
_Dipylidium_, 81, _91_;
life-history, 83, 88, 89;
specific characters, 90
Disc, in Rotifers, 200, 202 f., 202
Discharge, of genital cells;
Nemertinea, 116;
Archiannelida, 244;
Polychaeta, 256, 274, 275
_Discobdella_, 226
_Discocelis_, _19_, 23
Discodrilidae, 350, _376_, 392, 395
_Discopus_, 201, _222_, 226, 227
_Dispharagus_, _147_, 149, 163
_Dispinthera_, _225_
_Distemma_, 212, _224_, 226
Distomatidae, _73_
_Distomum advena_ (= _D. migrans_), life-history, 71;
_D. appendiculatum_, life-history, 71;
_D. ascidia_, life-history, 71;
_D. atriventre_, life-history, 71;
_D. brachysomum_, life-history, 71;
_D. buskii_, 63;
_D. caudatum_, life-history, 71;
_D. clavigerum_, life-history, 72;
_D. conjunctum_, 63;
_D. crassum_, 63;
_D. cygnoides_, life-history, 72;
_D. cylindraceum_, 72;
_D. dimorphum_, 72;
_D. echinatum_, 63;
life-history, 72;
_D. echiuri_, 444;
_D. endolobum_, life-history, 72;
_D. excavatum_, 63;
_D. ferox_, 63;
_D. globiporum_, life-history, 72;
_D. hians_, 63;
_D. hepaticum_ (liver-fluke), 3, 63, 67 f.,72;
_D. heterophyes_, 63;
_D. hystrix_, life-history, 72;
_D. japonicum_ (= _D. spathulatum_), 63;
_D. lanceolatum_, 63;
_D. luteum_, excretory system of, 62;
_D. macrostomum_, life-history, 64, 65, 72;
_D. magnum_, 68;
_D. militare_, life-history, 72;
_D. nodulosum_, life-history, 72;
_D. oculi-humani_ (= _D. ophthalmobium_), 63;
_D. ovocaudatum_, life-history, 72;
_D. pulmonale_, 63, 70;
_D. rathouisi_, 63, 70;
_D. retusum_, life-history, 72;
_D. ringeri_ (= _D. pulmonale_), 63; {542}
_D. signatum_, life-history, 72;
_D. sinense_, 70; _D. spathulatum_, 63;
_D. squamula_, life-history, 72;
_D. trigonocephalum_, life-history, 72;
_D. westermanni_ (= _D. pulmonale_), 63
_Distyla_, _225_
_Dithyridium_, _91_
_Ditrupa_, 301
_Diurella_, _225_, 226
_Dochmius_, 133, 135, _142_, 160, 163;
_D. cernua_, 143;
_D. duodenalis_, 143, 163;
_D. stenocephala_, 143;
_D. trigonocephala_, 143
_Dodecaceria_, 287, _326_, 327
Dog, parasites of, 80 f., 90, 125, 140, 142, 143, 145
_Dolichoplana_, 37, _42_
Domestic animals, Trematodes of, 67, 68, 70, 72;
Cestodes of, 81, 89;
Nematodes of, 139 f., 163;
Acanthocephala of, 184
_Domopora_, 531, 532
Dorsal ciliated organ, 247, 254, 256
Dorsal pores, 348
_Dorylaimus_, 131, _157_, 160
_Dracunculus_, 131, 135, 147
_Drepanidotaenia_, _91_;
_D. anatina_, life-history, 84, 85;
_D. gracilis_, _D. infundibuliformis_, _D. setigera_, life-history, 84
_Drepanophorus_, excretory system, 108;
British species, _110_
Drilophagidae, _224_
_Drilophagus_, 204, 210, 212, _224_, 227
Dugès, on Planarians, 6, 10;
on Oligochaeta, 368
Dujardin, on Rotifers, 198;
on Gastrotricha, 231;
on Kinorhyncha, 236
Duplicature, 499, 500
_Duthiersia_, _91_
Dwarf males, of _Myzostoma_, 344;
of Gephyrea, 438

Ear-cockle, 155
Earthworms, 347, 365;
senses, 354;
food, 359;
effect on the soil, 368;
distribution, 369 f.;
classification, 380 f.;
British, 390—see also Oligochaeta
Ebrard, on Hirudinea, 393
_Echeneibothrium_, _91_
_Echinella_, _73_
_Echinobothrium_, 74, 75, 85, _91_
_Echinococcus_, 80, 83
_Echinocotyle_, _91_
_Echinoderes_, 236 f., 236
Echinorhynchidae, _182_
_Echinorhynchus acus_, 175, 179;
_E. angustatus_, 174, _183_;
_E. clavula_, _183_;
_E. haeruca_, 176;
_E. linstowi_, _183_;
_E. lutzii_, _183_;
_E. moniliformis_, _183_;
_E. proteus_, 174, 180, 181, 182, 182
_Echinosiphon_, 424, 429
Echiuroidea, 241 n., _412_, 434, 446;
anatomy, 434 f.;
classification, _440_;
development, 439;
parasites, 444;
habits, 442
_Echiurus_, 336, 411, 435, 440, _441_;
development, 439
Eckstein, on Rotifers, 198
_Eclipidrilus_, _380_
Economic uses, of Polychaeta, 296, 297
Ectocyst, 469, 470, 523;
of Phylactolaemata, 496 f., 503
Ectoderm, of Mesozoa, 93, 95
Ectoparasitic Trematodes, 4, 52, 53
Ectoprocta, _475_, _518_;
structure, 469;
lophophore, 476;
reproduction, 506 f.;
larva, 509, 510, 511;
compared with Entoprocta, 488
Effects, of parasites on their hosts, 56, 68, 69, 80, 94, 162
Eggs, of _Leptoplana_, 10, 16;
of Polyclads, 28;
of Triclads, 33, 40;
of Rhabdocoels, 47, 48;
of Termatodes, 52;
of ectoparasitic Trematodes, 54, 58, 60, 61;
of endoparasitic Trematodes, 63, 69;
of Cestodes, 87;
of Orthonectidae, 95;
of Nemertinea, 116;
of Nematoda, 135, 162;
of _Gordius_, 171;
of Acanthocephala, 179;
of Chaetognatha, 189;
of Rotifera, 200, 216 f.;
of Gastrotricha, 234;
of _Nereis_, 256;
of Polychaeta, 274, 275;
of Phyllodocids, 314;
of _Scoloplos_, 321;
of _Myzostoma_, 343;
of Polyzoa, 506, 507
Ehrenberg, on Turbellaria, 3, 6;
on Rotifers, 198, 220 n., 228;
on Gastrotricha, 231;
on Polyzoa (Bryozoa), 475
Eichhorn, on Rotifers, 197
Eisen, on Oligochaeta, 380, 390
Eisig, on Capitellidae, 373;
on _Bonellia_, 443
_Electra_, 481, _518_, 523, 530;
larva, 509, 510;
variation, 516
Elytra, of Polynoids, 265, 292, 294, 298, 299, 309, 310, 311;
phosphorescent, 295, 296;
as brood-pouch, 275;
of Aphroditidae, 266;
arrangement of, 309;
of Sigalionina, _313_
_Enantia_, 16 n., _19_
Enantiidae, _19_
_Enchelidium_, _157_
Enchytraeidae, 359, 360, 361, 366, 367, 370, _375_
_Enchytraeus_, host of _Gordius_, 173
_Encotylabe_, _73_;
eggs of _E. pagelli_, 58
Endocyst, 471
Endoderm, of Mesozoa, 93, 95
Endoparasitic Trematodes, 4, 52, 62
Enopla, 109
Enoplidae, _157_
_Enoplus_, 157, 160
_Entalophora_, _518_, 532
_Enteroploea_, _224
Enterostoma_, 46; {543}
British species, _50_
Entoprocta, _475_, 479, 487 f., _518_;
lophophore, 476;
reproduction, 506;
larva, 509, 510
_Eosphora_, 216, 218, _224_
_Ephemera_, host of _Gordius_, 172, 173
_Ephesia_, _321_
_Epibdella_, 55, _73_
Epidermis, of _Leptoplana_, 11, 12;
of Polyclads, 20, 25, 29;
of Trematodes, 56;
of Cestodes, 85;
of Nemertinea, 102;
of Nematoda, 125;
of Acanthocephala, 175;
of _Nereis_, 249;
of Oligochaeta, 349;
of Leeches, 396;
of Gephyrea, 414;
of _Phoronis_, 454—see also Hypodermis
Epigamous, phase, of _Nereis_, 277 n.;
worms, 281
Epistome, in _Phoronis_, 453, 455;
in Phylactolaemata, 476, 476, 499;
in larva of _Loxosoma_, 509
_Epistomia_, _518_, 526
_Epithetosoma_, 444, 445, 449
Epithetosomatoidea, _412_, 444
Epitokous, phase, of _Nereis_, 277 n.
_Eretmia_, _225_, 226
Eriographidae, _258_, _338_
_Erpocotyle_, _73_
Errantia, 258, 285
_Eschara_, 516
Escharina, _518_
_Escharoides_, 527
Euchlanididae, _225_
_Euchlanis_, _225_, 226
_Eucratea_, _518_, 525, 527, 528
Eudrilidae, 359, 360, 380, _385_, 403 f.
_Eudrilus_, 354, _385_, 403 f.
Euichthydina, _235_
_Eulalia viridis_, _314_;
pigment, 292;
colour, 293;
eggs, 314 n.
_Eumenia_, _334_
_Eunice_, 318, _319_;
nephridium, 254;
eye, 255;
head, 262;
parapodium, 264;
gill, 265;
chaetae, 266, 267;
jaws, 270;
substance of tube, 290;
commensal, 298;
_E. tibiana_, 290
Eunicidae, _258_, _318_;
palps, 260;
tentacles, 262;
jaws, 270;
tube, 285, 290;
colour, 291, 292;
parasitic, 297;
tubes containing Polynoids, 298;
Palaeozoic, 302
_Eunicites_, 301, 302
_Euphrosyne_, _318_;
parapodium, 265;
chaetae, 267
_Eupolia_, _113_
Eupolyzoa, 461
_Eurycercus_, shell of, inhabited by Rotifers, 227 n.
_Eurylepta_, _19_
Euryleptidae, _19_
_Eurythoe_, _318_
_Eustrongylus gigas_, _142_;
_E. tubifex_, _142_
_Eusyllis_, reproduction of, 278
Excretion, as cause of colour, 291
Excretory system, of _Leptoplana_, 13;
of Polyclads, 25;
of Triclads, 41;
absent in Acoela, 42;
of Temnocephala, 54;
of Digenea, 62;
of Cestodes, 86;
of Nemertinea, 108, 108, 120;
of Nematodes, 133;
of Acanthocephala, 177;
of Rotifers, 199, 213;
of Gastrotricha, 234;
of Kinorhyncha, 237;
of Polychaeta, 253;
of Polyzoa, 472 f.—see also Nephridium
_Exogone_, _308_;
attachment of eggs, 275;
reproduction, 278
Eyes, of _Leptoplana_, 8, 15;
of Polyclads, 26, 27;
development of, 30;
of larval Polystomatidae, 59, 60;
of Nemertinea, 102, 106;
of Nematodes, 128;
of _Gordius_, 166;
of Chaetognatha, 188;
of Rotifera, 215;
of Gastrotricha, 234;
of Kinorhyncha, 238;
of Polychaeta, 255, 272, 314, 337, 339;
of Oligochaeta, 354;
of Leeches, 393, 394, 395;
of Gephyrea, 417;
of Polyzoon larva, 509

_Fabricia_, _339_;
eyes, 272;
otocyst, 273
Faecal groove, of Sabellids, 337
Fans, of _Chaetopterus_, 295, 324
Faraday, on asexual reproduction of Planariae, 6, 40 n.
Farre, on Polyzoa, 500, 508
_Farrella_, 500, _518_, 533
_Fasciola_, 67
_Fecampia_, life-history, 45
Felt, of _Aphrodite_, 268, 312
Fertilisation, of Nemertinea, 117;
of Nematodes, 135;
of Gordiidae, 171;
of Acanthocephala, 179;
of Chaetognatha, 188;
of Rotifers, 217
_Filaria_, _147_, 163;
_F. attenuata_, 134;
_F. cystica_, 142;
_F. denticulata_, 125;
_F. immitis_, 148;
_F. labiata_, 163;
_F. laticaudata_, 125;
_F. loa_, 149;
_F. medinensis_, 147, 157, 163;
_F. sanguinis hominis_, 149, 163;
_F. papillosa_, 163
Filariidae, _147_
_Filigrana_, _340_;
fission in, 281;
tubes, 290
_Fimbria tenuis_, 157
Fischer, on branchiae in Gephyrea, 416 n.
Fishes, Trematodes of, 4, 53, 55, 62, 64, 71, 72;
Cestodes of, 77, 84, 85;
Nemathelminthes of, 142, 143, 149, 163, 173, 182
Fission, in _Bipalium_, 34;
in Planariae, 40;
in _Trichoplax_, 96;
in _Salinella_, 96;
in Polychaeta, 278 f., 279, 280, 282, 340;
in Oligochaeta, 374, 375, 377;
in Phylactolaemata, 496;
in embryos, 365, 511
_Fissurella_, as host, 298
_Flabelligera_, 334
Flame-cells, in _Leptoplana_, 13;
in _Thysanozoon_, 25;
in Triclads, 41;
in _Temnocephala_, 54;
in Polystomatidae and Tristomatidae, 56;
in _Distomum luteum_, 62;
in Cestodes, 86; {544}
in Nemertinea, 108, 109;
in Rotifers, 213;
in _Urnatella_, 491
_Fletcherodrilus_, _382_
_Floscularia_, 200, 203, 205, 220, _221_, 226
Flosculariaceae, 202, 211, 213, _220_
Flosculariidae, 201, 203, 205, _220_ n., _221_, 230
Flukes, 51
_Flustra_, 465, 466, 467, 472, 473, 477, 515, _518_, 526;
avicularia, 482
_Flustrella_, 467, 477, _518_, 532;
larva, 513
Flustrina, _518_
Food, of Turbellaria, 4;
of _Leptoplana_, 10;
of Polyclads, 24;
of Triclads, 37;
of Acoela, 43 f.;
of Rhabdocoela, 45;
of Trematodes, 4, 52, 62;
of _Temnocephala_, 53;
of Cestoda, 5;
of Nemertinea, 115;
of Nematodes, 131;
of Acanthocephala, 177;
of Chaetognatha, 190;
of Rotifera, 207, 212;
of Gastrotricha, 234;
of Polychaeta, 296;
of Earthworms, 359;
of Leeches, 393, 406 f.;
of Gephyrea, 422, 443;
of Polyzoa, 467
Foot, in Rotifers, 200, 201
Foraminifera, as food of Polychaeta, 296
Forceps, of _Eunice_, 270
Forcipate, 210, 211
Formula, for Nematoda, 138
Fornix, 481, 517, 525
Fossil, Polychaeta, 301;
Polyzoa, 520;
Nemertinea, absence of, 119
_Fredericella_, 476, 494, 502-505, _518_, 519;
lophophore, 495;
statoblast, 502, 503
Frenzel, on Trematoda, 62;
on _Salinella_, 96
Fresh-water, Turbellaria, compared with marine, 46;
Nemertinea, 101, 118;
Polychaeta, 284;
Polyzoa, 492
Friend, on Oligochaeta, 388 n.
Frogs, Trematodes of, 55, 58, 62, 71 f.;
Nematodes of, 140, 142, 160, 173
Frontal organ, of Nemertinea, 107
Frontal palps, of Eunicidae, 318 f.
Frontal ridge, 260
_Frullania_, inhabited by Rotifers, 227
Fulcrum, in Rotifers, 210
Funicular tissue, 471
Funiculus, 469, 471, 472, 499, 501
_Furcularia_, 216, _224_, 226

Gamble, on Platyhelminthes, 3 f.;
on Mesozoa, 92 f.
_Gammarus_, Rotifers attached to, 227
Gapes, cause of, 144
Gardiner, on development of Acoela, 44 n.
Gasterostomatidae, _73_
_Gasterostomum_, _73_;
_G. fimbriatum_, life-history, 72;
_G. gracilescens_, 72
_Gastrocotyle_, _73_
_Gastrodiscus_, _73_
_Gastrothylax_, _73_
Gastrotricha, 231 f.
Gegenbaur, on Nemertine development, 99
_Gemellaria_, _518_, 526
Gemmation, 281;
in Syllidae, 278 f., 279, 280
_Geobia_, 37
_Geodesmus_, 34, _42_
Geographical distribution, of Turbellaria, 32 f.;
of Nemertinea, 117;
of Chaetognatha, 191, 534;
of Gastrotricha, 235;
of Polychaeta, 299 f.;
of Oligochaeta, 369 f.;
of Leeches, 405;
of Gephyrea, 426 f., 432, 441 f.;
of _Phoronis_, 460;
of Polyzoa, 492 f., 504, 519
_Geonemertes_, 101;
description of _G. chalicophora_, 117
_Geoplana_, 33, 38, _42_
Geoplanidae, 35, _42_
Geoscolicidae, 351, 362, _386_
Gephyrea, 411 f.;
history, 411;
external characters, 412, 420 f., 430 f., 434 f., 444;
body-wall, 414, 436;
digestive system, 414, 422, 430, 436, 445;
vascular system, 415, 421, 436;
respiratory system, 416;
body-cavity, 416, 437, 445;
nervous system, 416, 431, 437, 445;
excretory system, 417, 423, 431, 437, 445;
reproductive system, 418, 431, 437, 445;
development, 419, 439;
food, 422, 443;
commensalism, 429;
affinities, _241_ n., 336, 445 f., 512;
British, 449
Germarium, of Rotifers, 216
Germ-yolk-gland, 47
Giard, on Oligochaeta, 368
Gid, induced by _Coenurus_, 82
Gigantorhynchidae, _183_
_Gigantorhynchus gigas_, 174, 177, _184_;
_G. echinodiscus_, _G. spira_, _G. taenioides_, _184_
Gills, of Polychaeta, 252, 265, 268 f.;
of _Arenicola_, 333;
of Chlorhaemidae, 334;
of _Cirratulus_, 326;
of _Euphrosyne_, 265, 318;
of Eunicidae, 318;
of _Nereis_, 246;
of Sabelliformia, 260, 261;
development of, 275;
of _Sabella_, 286;
colour of, 294;
of _Sabellaria_, 263;
of Serpulidae, 261;
of _Sternaspis_, 336;
of Sigalionina, 313;
of Terebellidae, 329;
of Oligochaeta, 352, 353;
of Leeches, 395;
of Gephyrea, 416
Gizzard, in Rotifers, 199, 210;
in Polychaeta, 271, 307;
in Oligochaeta, 358;
in Polyzoa, 477, 480, 532 f.
Glands, on parapodia, 249;
of Phyllodocids, 314;
oesophageal, 271, 272, 358;
tube-forming, 287, 304, 327
Gland shields, 287, 304, 306;
of Sabellids, 337;
of Terebellids, 327
Glandular papillae, of _Polygordius_, 244
_Glossiphonia_ (= _Clepsine_), 393, 396, 399, 404, _407_; {545}
anatomy, 397, 398, 401;
spermatophore, 402
Glossiphoniidae, _406_
_Glycera_, cirrus, 265;
habitat, 286;
jaws, 270;
nephridium, 254;
parapodium, 264;
prostomium, 259;
tentacles, 262;
_G. capitata_, distribution, 299;
_G. meckelii_, 320
Glyceridae, _258_, _320_;
gills, 268;
coelomic corpuscles, 253
_Glyphidrilus_, _386_
Gnathobdellae, 396 f., _407_
Gnathobdellidae, _407_
_Gnathosyllis_, colour of, 293
_Gobio_, parasites of, 182, 183
_Golfingia_, _426_, 428, 430
_Goniada_, _320_
Goodrich, on Oligochaeta, 378
Gordiidae, _123_, 164 f.
_Gordiodrilus_, _383_ f.
_Gordius_, 164 f., 164;
_G. tolosanus_, 165 f., 170
Gosse, on Rotifers, 198, 209 n., 220
_Gossea_, 232, _235_
Goujon, on _Trichina_, 146
Gourret, on Chaetognatha, 187
Graff, von, on Rhabdocoelida, 44;
on _Geonemertes_, 101, 117
_Graffilla_, _50_;
occurrence, 45
Grassi, on Cestoda, 80 n., 89;
on Chaetognatha, 190, 193
Grater, of Eunicidae, 270
Greef, on Echiuroidea, 441, 444
Gregarines, in Polychaeta, 299;
in Gephyrea, 444
Gregory, on Polyzoa, 519, 520
Grinder, of Eunicidae, 270
Grube, on Oligochaeta, 347, 352;
on Hirudinea, 395
_Grubea_, _308_;
attachment of eggs, 275
Guanin, in coelomic corpuscles, 253
Guinea-worm, 147
_Gunda_, 31, 41, _42_
Gundidae, 42
Gymnolaemata, _476_, 512, _518_;
lophophore, 476;
in fresh water, 492
_Gyrator hermaphroditus_, _49_
_Gyrocotyle_ (= _Amphiptyches_), _91_;
_G. rugosa_, 77;
_G. urna_, 77
Gyrodactylidae, _53_, 61, _73_
Gyrodactylinae, _73_
_Gyrodactylus_, 55, 61, _73_