Chapter XL: Section IV: STICHOCYRTIDA, Haeckel, 1862, Monogr. d. Radiol., p. 280, 312 (15)

The large hollow tubes which arise from the galea of all Coelographida, are very variable in number, size and shape, but are always richly branched and symmetrically arranged in the dorsal and the ventral valve of the shell. They exhibit an important difference in the two subfamilies of the group; in the Coelotholida all the branches, and also the thin terminal ramules, are free, without any junction; in the Coeloplegmida, however, they communicate by frequent anastomoses, and the connected terminal ramules form on the surface of the calymma an outer lattice-mantle of very delicate network. Another marked difference between the two families is indicated by the origin and site of those main tubes which are connected with the rhinocanna by a frenulum. In the Coeloplegmida an odd, very large main tube (the nasal style) arises from the anterior apex of each galea and bears on its base an odd frenulum. This nasal style and its frenulum is altogether wanting in the Coelotholida, where two paired main tubes (the frontal tubes) arise from the lateral corners of the truncate anterior side of the galea, and are connected with the mouth of the rhinocanna by two paired convergent lateral frenula.

We distinguish in all Coelographida two different forms of hollow branched tubes, which we will call "brushes" and "styles." The brushes are dichotomously branched from the base, not verticillate; their distal ramules remain separate in the Coelotholida {1744}and compose the spiny surface, of the peculiar "fork-thicket" whilst in the Coelographida they become connected by frequent anastomoses and form the outer "lattice-mantle." The styles however are much longer projecting over the surface of the thicket or the mantle, and are not dichotomously branched, but verticillate, or armed with cruciate or alternately cruciate pairs of branches; the larger branches of the styles may be again dichotomously branched like the brushes; whilst the free prominent parts of the styles are always verticillate or cruciate-pinnate. The brushes are identical with the hollow tubes of the Coelodendrida, whilst the styles are peculiar forms of apophyses, wanting in the latter.

The minimum number of hollow tubes which arise from each valve is three, and these are probably homologous with the three primary tubes of the Coelodendrida. Two of these are paired (right and left), whilst the third is odd and lies in the sagittal plane; they have the same position as in the tripodal NASSELLARIA, and may therefore bear the same names, the two paired anterior or pectoral tubes being divergent forwards, the odd or caudal tube being bisected backwards (so in the Coelotholida, Pl. 121). The odd caudal tube (probably identical with the odd tube of the Coelodendrida) is always a brush, dichotomously branched, and never prolonged into free style. The two paired frontal or pectoral tubes, however are usually prolonged into two long verticillate styles. The basal origin also of these three primary tubes is different. The two pectoral or anterior paired tubes always arise from the galea itself whilst the posterior odd or caudal tube usually arises behind the galea from the valve (Pl. 127, figs. 4-8, _g_ 6).

Since these three primary tubes the odd caudal and the paired pectoral, are probably homologous in all Coelographida and Coelodendrida, they have a great morphological importance, similar to the three primary feet of the NASSELLARIA. All other tubes arising from the valves must be regarded as secondary apophyses, since they are not constant in all members of the two families, but present only in some of them. All the Coelotholida observed (a small number of species only) possess no secondary tubes, but only the three primary; whilst all Coeloplegmida possess one or more secondary tubes, and one of these is constant, viz., the odd nasal style, directed towards the mouth, and arising as the foremost from the apex of the galea (Pl. 127, figs. 4-8, _g_ 1).

The maximum number of tubes observed, which arise from each valve in the Coeloplegmida, is eleven; five of these are odd and placed in the sagittal plane of the body, viz.:--(A) the primary caudal tube (Pl. 127, figs. 4-8, _g_ 6); (B) an odd procaudal tube, arising between the caudal and the sagittal tube; (C) the sagittal tube, placed either in the sagittal axis of the body or near it (often prolonged into a sagittal style, Pl. 128, fig. 1); (D) an odd postnasal tube, arising between the sagittal and the nasal tube; (E) the odd nasal tube, constant in all Coeloplegmida, and connected at its base by the odd frenulum with the rhinocanna (Pl. 127, figs. 4-8, _g_ 1). All other tubes occurring in the Coeloplegmida are paired, and symmetrically arranged on both sides of the sagittal {1745}plane, at right and left; their maximum number is three pairs, viz.:--(F) the paired pectoral tubes (as the foremost), directed forwards; (G) the paired frontal or lateral tubes, placed either in the frontal axis of the valve, or in a neighbouring axis, directed towards the right and left pole (Pl. 127, figs. 4-8, _g_ 4 and _g_ 5); (H) the paired tergal tubes, directed backwards (constant in all Coeloplegmida). The origin of these tubes is rather variable, since they arise in nearly allied species, sometimes independently of one another, at other times united at the base. But a closer comparison of them in the different species will demonstrate their homology, caused by constant heredity.

The terminal ramules of the brushes, which form the subspherical "fork-thicket" in the Coelotholida, the outer "lattice-mantle" in the Coeloplegmida, are constantly armed at the distal ends either with spathillæ or with anchor-pencils, bunches of those most elegant spinulate threads, which bear at the free end an anchor, or a whorl of two, three, or four recurved teeth (Pl. 122, fig. 8; Pl. 127, fig. 10; Pl. 128, figs. 1, 6). The pencils are usually dichotomously branched, their threads zig-zag or delicately serrate, often armed with very small recurved denticles, and the anchor teeth (commonly three or four) are usually smooth on the convex outer, serrate on the concave inner edge. The entire surface of the subspherical thicket in the Coelotholida, and of the polyhedral lattice-mantle in the Coeloplegmida, is armed with thousands of those most elegant spathillæ, or anchor-pencils.

The "fork-thicket" of the Coelotholida is identical with that of the Coelodendrida, and is composed only of the innumerable dichotomous branches of the hollow tubes. It envelops the two central valves and the enclosed central capsule in the same way as in the Coelodendrida. But the Coelotholida differ from these latter in constantly possessing a rhinocanna and two frenulæ. The entire form of this thicket, which in the few species observed was never complete, but always more or less destroyed, is usually probably subspherical or polyhedral, sometimes cordate or kidney-shaped. Its surface is densely studded with thousands of spathillæ. Its diameter is about four to eight times as great as that of the enclosed bivalve shell.

The "lattice-mantle" of the Coeloplegmida, which replaces in this subfamily the fork-thicket of the Coelotholida, is always produced by the anastomoses of the distal ramules of the brushes, and of those branches of the styles which do not proceed over the surface of the mantle. Its network is always very irregular, and composed of polygonal meshes of very different sizes. Usually it is quite simple, and may be compared with the cortical shell of the Disphærida. More rarely it is more or less spongy. Its surface is densely studded with thousands of spathillæ or anchor-pencils. The entire form of the lattice-mantle is always symmetrically polyhedral, since its dorsal and ventral halves are symmetrically developed on both sides of the equatorial plane, and therefore correspond perfectly to the enclosed smaller halves of the central bivalve shell. The two valves of the lattice-mantle (dorsal and ventral valves) are never really united and grown together, {1746}but are in loose contact in the equatorial plane; here the free edges of both valves catch into one another by means of free ramules (Pl. 128, figs. 1, 7). This loose connection is similar to what occurs in the Conchopsida (or in the Concharida with dentate edges), but never so regular. The special form of the polyhedral lattice-mantle depends on the number, arrangement, and development of the styles, which proceed over its surface; it preserves the polyhedral form of the calymma, on the surface of which it is deposed.

The characteristic styles of the Coelographida (which are never found in the preceding Coelodendrida) are longer hollow tubes, symmetrically disposed on both valves. They are prominent over the surface of the fork-thicket in the Coelotholida, of the lattice-mantle in the Coeloplegmida. They bear in these latter a peculiar terminal coronet on their distal end, whilst in the former this end is armed with large pencils of spathillæ. The styles may be forked once or twice at their base, but in their greatest part they are verticillate, and not dichotomously branched like the brushes. The lateral branches of the styles are usually very numerous and regularly cruciate in alternating opposite pairs. In the odd nasal style, _e.g._, the first and third pairs of opposite lateral branches usually lie in the frontal plane, the second and fourth in the sagittal plane, perpendicular to the former, and so on. A similar regular disposition of the lateral branches is found also in other styles, but not in all. There are certain styles in which the lateral branches are not opposite in pairs, but alternate or verticillate, and others in which they represent unequal branches of forks, so that each single segment of the branched style represents the stouter branch of a fork, and the appertaining lateral branch the thinner branch of the fork. Further accurate examinations are required to recognise the different laws of the ramification of the styles in the different forms of Coelographida. The lateral branches of the styles are usually again dichotomously branched inside the lattice-mantle, and their distal ends pass over into its network. But the verticillate or cruciate branches, which arise from the free part of the styles outside the lattice-mantle, are always armed with the same elegant pencils of spathillæ which cover the surface of the fork-thicket in the Coelotholida, the surface of the lattice-mantle in the Coeloplegmida. These pencils also are often regularly opposite in pairs, and the pairs alternate in two planes perpendicular one to another (Pl. 128, figs. 1, 4).

The terminal coronets are peculiar ornaments which protect the distal ends of the styles in the Coeloplegmida, whilst in the Coelotholida these are armed with the usual pencils of spathillæ (Pl. 122, fig. 8). Each coronet is usually produced by the double, triple, or quadruple furcation of the free distal end of the style; therefore composed of four, eight, or sixteen terminal branches, which, on account of their peculiar form and function, we may call "fingers." More rarely the ramification of the coronets is more or less irregular, and sometimes the number of the fingers exceeds twenty or even thirty.

In the majority of species eight fingers are regularly disposed (Pl. 127, figs. 1-3; Pl. 128, figs. 1-8). Often too sixteen occur, rarely four only. Sometimes the fingers {1747}are placed nearly in one plane and form a hand. The form of the fingers is very variable and most characteristic of the individual species. Very often they have the shape of a human finger, and are smooth, spinulate, or armed with recurved hooks. The distal end of each finger often again bears a small coronet or a spathilla (Pl. 128, figs. 5-9), and sometimes it is arrow-shaped (Pl. 126, fig. 2_a_). All these apophyses of the terminal coronets as well as the anchor-pencils of the mantle and the finest branches of the tubes, are hollow and filled up by jelly.

The different number and arrangement of the styles offers the best means for the distinction of genera in the Coelographida. The minimum number is six (_Coelographis_, Pl. 126, fig. 1), the maximum number sixteen (_Coelothamnus_, Pl. 122, fig. 3, and _Coelagalma_, Pl. 126, fig. 4). Since the arrangement of the styles in both valves is constantly symmetrical, the fundamental form of the whole body is in all Coeloplegmida "amphithect," as in the _Ctenophora_. The longitudinal or main axis of the body is vertical, with two distinct poles; the proboscis of the central capsule and the two rhinocannæ are directed upwards, towards the oral pole; the caudal tube of each valve is directed downwards, towards the aboral pole. The two other axes of the body are unequal, horizontal, and perpendicular one to the other; each has two equal poles. On the poles of the sagittal axis lie the galeæ of the dorsal and ventral valves; on the poles of the frontal axis lie the two secondary openings or parapylae of the central capsule. The frontal fissure or the large cleft between the dorsal and ventral valves of the skeleton lies in the vertical frontal plane of the body, which is perpendicular to the vertical sagittal plane; the equatorial plane, however, is horizontal.

The _central capsule_ of the Coelographida exhibits the same shape and position as in the preceding Coelodendrida. It is subspherical, slightly depressed in the direction of the main axis, and lies enclosed between the two central valves of the lattice-shell. Its three constant openings lie in the frontal plane, and therefore in the frontal fissure between the two valves. The astropyle, or the main-opening of the capsule, lies on the oral pole of the main axis, and its radiate operculum (_d_) is directed upwards; the curved proboscis arising from it (_o_) is prominent between the mouths of the two opposed rhinocannæ. The two lateral parapylæ or accessory openings lie on both sides of the aboral pole, on the right and left (Pl. 127, figs. 4-6). The large spheroidal or somewhat lenticular nucleus (_n_) is usually about half as broad as the capsule, and contains numerous nucleoli. The protoplasm around the nucleus contains many vacuoles, and in the oral part of the capsule (between nucleus and operculum) often numerous groups of crystals (Pl. 127, figs. 4-6_k_, 7). The double membrane of the central capsule exhibits the same shape as in the other PHÆODARIA.

The calymma, or the extracapsular jelly-veil, is in the Coelographida very voluminous, and includes the entire skeleton, the fork-thicket of the Coelotholida, the lattice-mantle of the Coeloplegmida, and also the prominent large styles. Only the distal ends of the {1748}latter (with the terminal coronets), and the anchor pencils, covering the surface of the thicket and the mantle, seem to project over the surface of the calymma. The entire form of the latter is therefore a symmetrical polyhedron. The phæodium fills up a small part only of the calymma, and is usually enclosed in the two galeæ and their rhinocannæ (Pl. 127, figs. 5, 9), but often also a part of the phæodium is scattered around the oral half of the central capsule.

_Synopsis of the Genera of Coelographida._

-------------------------------------------------------------------------
I. Subfamily Coelotholida.
Rhinocanna of each valve with two paired lateral frenula. The distal
ends of the dichotomous brushes are not united by anastomoses, and
form an outer bivalved fork-thicket.
-------------------------------------------------------------------------
Eight paired styles (four on each valve), 731. _Coelotholus_.

Twelve paired styles (six on each valve), 732. _Coelothauma_.

Sixteen paired styles (eight on each valve), 733. _Coelothamnus_.
-------------------------------------------------------------------------
II. Subfamily Coeloplegmida.
Rhinocanna of each valve with an odd sagittal frenulum. The distal
ends of the dichotomous brushes are united by anastomoses, and form
an outer bivalved lattice-mantle.
-------------------------------------------------------------------------
Mantle with six styles. { One odd and two paired
{ styles on each valve, 734. _Coelographis_.

Mantle with eight styles. { Two odd and two paired
{ styles on each valve, 735. _Coelospathis_.

Mantle with ten styles. { One odd and four paired
{ styles on each valve, 736. _Coelodecas_.

Mantle with twelve { Two odd and four paired
styles. { styles on each valve, 737. _Coelostylus_.

Mantle with fourteen { One odd and six paired
styles. { styles on each valve, 738. _Coeloplegma_.

Mantle with sixteen { Two odd and six paired
styles. { styles on each valve, 739. _Coelagalma_.

Subfamily 1. COELOTHOLIDA, Haeckel.

_Definition._--#Coelographida# with two paired lateral frenula on each galea, and with free terminal branches on the hollow radial tubes, without an external lattice-mantle. Eight to sixteen long styles are prominent over the surface of the fork-thicket, which is composed of the caudal brush and the dichotomous basal branches of the styles.

Genus 731. _Coelotholus_,[347] n. gen.

_Definition._--#Coelographida# with two paired lateral frenula on each galea, without external lattice-mantle, armed with eight styles (two pairs of styles on each valve).

{1749}The genus _Coelotholus_ and the two following genera form together the subfamily Coelotholida, the hollow tubes of which do not communicate by anastomosing branches, and therefore form no lattice-mantle, as in the following subfamily Coeloplegmida. Another important difference between these two subfamilies of Coelographida is found in the arrangement of the main tubes and their connection with the rhinocanna. In all Coelotholida a pair of divergent frontal styles arise from the truncate oral side of each galea, and are connected with the mouth of the rhinocanna by two lateral convergent paired frenula (right and left); whereas the characteristic odd nasal style, which in all Coeloplegmida arises from the sagittal apex of each galea and is connected with the mouth of the rhinocanna by an odd sagittal frenulum, is always wanting. The total number of long verticillate styles, which project over the outer surface of the fork-thicket, is eight in _Coelotholus_, whilst it is twelve in _Coelothauma_, and sixteen in _Coelothamnus_. The two latter may be derived from _Coelotholus_, as the common ancestral genus of this subfamily.

1. _Coelotholus octonus_, n. sp. (Pl. 122, figs. 1, 2).

Eight styles of equal length, regularly zig zag, twice as long (in their free part) as the diameter of the loose fork-thicket. Anchor-pencils gradually tapering from the proximal towards the distal end. Each of the four primary frontal tubes (to the right and left of each valve) is simply forked, and the pectoral (anterior) branch of each tube is so diametrically opposed to the tergal (posterior) tube of the other side, that they form together a double cross.

_Dimensions._--Diameter of the whole body 12, of the fork-thicket 2.5.

_Habitat._--South-Eastern Pacific, Station 300, depth 1375 fathoms.

2. _Coelotholus cruciatus_, n. sp.

Eight styles of equal length, straight, twice as long (in their free part) as the diameter of the dense fork-thicket. Anchor-pencils of about equal size throughout their whole length. Each of four primary frontal tubes is divided into two equal, widely divergent branches; the anterior branches of the right side are diametrically opposed to the posterior branches of the left side, so that all eight together form a double cross.

_Dimensions._--Diameter of the whole body 20, of the fork-thicket 4.0.

_Habitat._--South-Western Pacific (off Sydney), Station 164A, depth 1200 fathoms.

3. _Coelotholus ancoratus_, n. sp.

Eight styles of different lengths, slightly curved. Anchor-pencils gradually tapering from the proximal to the distal end. Each of the four primary frontal tubes is divided into two divergent {1750}branches of different lengths; the anterior (or pectoral branch) twice as long (in the free part) as the diameter of the fork-thicket, the posterior (or tergal branch) three times as long.

_Dimensions._--Diameter of the whole body 20, of the fork-thicket 3.2.

_Habitat._--Indian Ocean (Sunda Strait), Rabbe, surface.

Genus 732. _Coelothauma_,[348] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 6.

_Definition._--#Coelographida# with two paired lateral frenula on each galea, without external lattice-mantle, armed with twelve styles (three pairs of styles on each valve).

The genus _Coelothauma_ differs from the preceding _Coelotholus_, its ancestral form, in the possession of twelve long, prominent styles, six of which are opposite in three pairs on each valve. In the single species observed each of the four main tubes (opposite in pairs on the frontal corners of the two galeæ) is simply forked, as in _Coelotholus_; but whilst in this latter all eight styles remain simple, in _Coelothauma_ the anterior (or pectoral) branch only is simple, the posterior (or tergal) branch is again forked.

1. _Coelothauma duodenum_., n. sp. (Pl. 122, figs. 3-5).

Twelve styles straight, of different lengths. Two short bilateral main tubes arise opposite in pairs from the two frontal corners of each galea, and are divided into an anterior and posterior branch. The anterior or pectoral branch is simple, and twice as long as the diameter of the fork-thicket. The posterior or tergal branch is again forked near the base, and its two divergent branches are three times as long as the diameter of the fork-thicket. All twelve styles are densely studded with anchor-pencils of nearly equal size.

_Dimensions._--Diameter of the whole body 21, of the fork thicket 3.5.

_Habitat._--South-Western Pacific (east of New Zealand), Station 169, depth 700 fathoms.

Genus 733. _Coelothamnus_,[349] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 6.

_Definition._--#Coelographida# with two paired lateral frenula on each galea, without external lattice-mantle, armed with sixteen styles (four pairs of styles on each valve).

The genus #Coelothamnus# differs from its ancestral form, _Coelotholus_, in the duplication of the number of long verticillate styles, which are prominent over the surface of the {1751}dense fork-thicket. Whilst in _Coelotholus_ each frontal main tube (arising from the frontal corner of the galea at right and left) is divided into an anterior or pectoral, and a posterior or tergal style, in _Coelothamnus_ each of these two divergent main styles is again forked, so that the total number of projecting and radially diverging styles amounts to sixteen. One Mediterranean species of this genus, _Coelothamnus davidoffii_, has been already described by Bütschli in 1882 (Zeitschr. f. wiss. Zool., vol. xxxvi. p. 486, Taf. xxxi.). Though its description on the whole is accurate, some important errors, which may be here corrected, are to be met with. The two central valves of the lattice-shell (dorsal and ventral) are symmetrically equal in size and in form, as in all other Coelographida; the different forms and the inverse arrangement of the two valves, described by Bütschli (pp. 488, 491), were effected by an artificial dislocation and inversion. The peculiar opening [alpha], which, according to his opinion, was supposed to bring about a direct communication between the cavities of the galea and its valve, is in reality the optical section of the rhinocanna, the two convergent frenula of which ([gamma]) he figured, but did not recognise. _Coelothamnus_ attains the greatest size among all Radiolaria; the diameter of the body in _Coelothamnus maximus_ amounts to 33 mm.

1. _Coelothamnus bivalvis_, n. sp. (Pl. 122, figs. 6-9).

Sixteen styles all of equal length, about three times as long (in their free part) as the diameter of the dense fork-thicket. The size of the anchor-pencils tapers from the proximal to the distal end. Each of the four primary frontal tubes (which arise in opposite pairs from the frontal corners of the two galeæ) is twice forked, and so produces four styles.

_Dimensions._--Diameter of the whole body 18, of the fork-thicket 2.4 to 3.0.

_Habitat._--North Atlantic, Canary Islands, Station 354, surface.

2. _Coelothamnus davidoffii_, Bütschli.

_Coelothamnus davidoffii_, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol.
xxxvi. p. 486, Taf. xxxi.

Sixteen styles all of equal length (?), about four times as long (in their free part) as the diameter of the fork-thicket. The size of the anchor-pencils is nearly equal throughout their entire length. (Compare the careful description of this species by Bütschli.)

_Dimensions._--Diameter of the whole body 15, of the fork-thicket 1.8.

_Habitat._--Mediterranean (Villafranca, near Nice), Davidoff, surface.

3. _Coelothamnus sedecimalis_, n. sp.

Sixteen styles straight, of different sizes. The pectoral or anterior branch of each frontal main tube is simple, and twice as long as the diameter of the large fork-thicket. The tergal or posterior branch is forked at the base, and its anterior branch is again forked in the middle part, so that three {1752}long divergent styles arise from each tergal tube. The hindermost of these is the longest, three times as long as the diameter of the fork-thicket. All anchor-pencils have nearly equal size.

_Dimensions._--Diameter of the whole body 22, of the fork-thicket 5.2.

_Habitat._--South Pacific, Station 166 (west of New Zealand), depth 275 fathoms.

4. _Coelothamnus maximus_, n. sp.

Sixteen styles straight, of different sizes. The four frontal main tubes are already forked at the base, so that from each frontal corner of the two galeæ two divergent tubes, an anterior or pectoral and a posterior or tergal, arise. Each of these is again forked, and each branch prolonged into a very long verticillate style. The hindermost style of each side is the longest, twice as long as the foremost, and one and a half times as long as the two intermediate styles. The size of the anchor-pencils decreases in the distal third of the styles.

_Dimensions._--Diameter of the whole body 32, of the fork-thicket 7.5.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

Subfamily 2. COELOPLEGMIDA, Haeckel.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea, and with an external bivalved lattice-mantle, produced by the anastomosing branches of the hollow radial tubes. Six to sixteen long styles are prominent over the surface of the mantle, and bear terminal coronets.

Genus 734. _Coelographis_,[350] n. gen.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with six styles (one odd and two paired styles on each valve).

The genus _Coelographis_ is the simplest form of the Coeloplegmida, or of those Coelographida in which the branches of the arborescent tubes are united on the surface of the calymma, and form a delicate bivalved lattice-mantle. In all these Coeloplegmida an odd nasal main style is developed on the apex of the galea, and this is connected by an odd sagittal frenulum with the mouth of the rhinocanna, _Coelographis_ differs from the other Coelographida in the minimum number of coronal styles, viz., three on each valve, an odd anterior (nasal) and two paired posterior (tergal).

1. _Coelographis regina_, n. sp. (Pl. 126, figs. 1_a_-1_c_).

Shell-mantle twice as long as broad, its frontal perimeter isosceles triangular, with a triangular excision at the base, its sagittal perimeter slenderly ovate. Nasal odd style twice as long as the {1753}paired tergal styles, the former with ten to twelve, the latter with five to six alternate-cruciate pairs of lateral branches. Terminal coronets (on the free distal ends of the styles) palmate, with ten to twelve spinulate, irregular, finger-shaped branches (fig. 1_d_).

_Dimensions._--Length of the shell 5.6, breadth 2.7.

_Habitat._--South-Eastern Pacific (off Juan Fernandez), Station 297, depth 1775 fathoms.

2. _Coelographis sagittella_, n. sp.

Shell-mantle one and a half times as long as broad, its frontal perimeter arrow-shaped, isosceles triangular, with a deep concave excision at the base, its sagittal perimeter slenderly ovate. Nasal odd style one and a half times as long as the paired tergal styles, the former with fourteen to sixteen, the latter with eight to nine verticils of branches. Terminal coronets three times forked, with eight subregular, broad and spinulate, finger-shaped branches.

_Dimensions._--Length of the shell 6.4, breadth 4.2.

_Habitat._--Central Pacific, Station 271, depth 2425 fathoms.

3. _Coelographis hexastyla_, n. sp.

Shell-mantle one and a half times as long as broad, very similar to the preceding species, its frontal perimeter isosceles triangular, with a flat basal excision. Nasal odd style one and a third times as long as the paired tergal styles, the former with fourteen to sixteen, the latter with ten to twelve verticils of branches. Terminal coronets with four forks in the form of a cross, and eight divergent spinulate fingers.

_Dimensions._--Length of the shell 4.2, breadth 3.1.

_Habitat._--North Pacific, Station 259, depth 2225 fathoms.

4. _Coelographis gracillima_, Haeckel.

_Coelodendrum gracillimum_ (_partim_) Haeckel, 1862, Monogr. d. Radiol.,
Taf. xxxii. figs. 2, 3.

Shell-mantle one and a third times as long as broad, similar to the three preceding species, its frontal perimeter isosceles triangular. Nasal odd style one and a half times as long as the two paired tergal styles, the former with eleven or twelve, the latter with seven or eight pairs of branches. Terminal coronets irregularly dichotomously branched, with twelve to sixteen spinulate fingers. The network of the mantle is also spinulate (_loc. cit._, fig. 3). This species was formerly confounded by me with _Coelodendrum gracillimum_ (_loc. cit._, fig. 1), since I found a fragment only of the former entangled in the branch-work of the latter (1859, in Messina). Afterwards (in 1877) I observed a complete specimen in Corfu.

_Dimensions._--Length of the shell 3.2, breadth 2.4.

_Habitat._--Mediterranean (Messina, Corfu), surface.

5. _Coelographis triangulum_, n. sp.

Shell-mantle about as long as broad, its frontal perimeter equilateral triangular, without basal excision, with three equal straight sides. Nasal odd style and the two paired pectoral styles nearly {1754}of equal length, each with ten to twelve alternate-cruciate pairs of lateral branches. Terminal coronets umbrella-shaped, composed of eight equal, simply forked branches.

_Dimensions._--Length of the shell 3.6, breadth 3.4.

_Habitat._--South Pacific, Station 293, depth 2025 fathoms.

Genus 735. _Coelospathis_,[351] n. gen.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with eight styles (two odd and two paired styles on each valve).

The genus _Coelospathis_ differs from the preceding _Coelographis_ in the possession of four coronal styles on each valve. Two of these are odd and lie in the sagittal plane, viz., the constant vertical nasal style (directed towards the mouth), and the horizontal sagittal style, which is placed in the equatorial plane, in the sagittal axis of the body. The two other styles are paired and identical with the tergal styles of _Coelographis_, directed backwards, and divergent to right and left.

1. _Coelospathis ancorata_, n. sp. (Pl. 128, figs. 1-7).

Shell-mantle one and a half times as long as broad, its frontal perimeter isosceles triangular; its zonal perimeter square, its sagittal perimeter nearly rectangular, with a concave excision on the oral side (fig. 1). Odd nasal styles of both valves divergent in the sagittal plane (each with fourteen to sixteen pairs of branches), three times as long as the odd sagittal styles (each with three or four pairs) and twice as long as the paired tergal styles (each with four to six pairs of branches). Terminal coronets (on the free distal end of the styles) three times forked, each with eight slender, widely divergent fingers, which are curved, zig-zag, and armed with alternating recurved hooks; at the end of each finger a verticil of four to six small recurved teeth (fig. 5).

_Dimensions._--Length of the shell 2 to 3, breadth 1.2 to 2.1.

_Habitat._--South Pacific, Station 289, depth 2550 fathoms.

2. _Coelospathis octostyla_, n. sp. (Pl. 128, fig. 8).

Shell-mantle one and a third times as long as broad, very similar to the preceding species; but differing from this in the following characters: the odd nasal styles bear ten to twelve pairs of branches, and are twice as long as the odd sagittal and the paired pectoral styles, which are nearly equal in size (each with five or six pairs of branches). The eight fingers of the terminal coronets are less divergent and curved than in the preceding species, and each finger bears at its end a verticil of four to six divergent, slender teeth, which are not recurved (fig. 8).

_Dimensions._--Length of the shell 2.2 to 2.6, breadth 1.7 to 1.9.

_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.

{1755}3. _Coelospathis octodactyla_, n. sp. (Pl. 128, fig. 9).

Shell-mantle about as long as broad, in the frontal perimeter nearly isosceles triangular, very similar to the two preceding species; it differs from them in the following characters: all eight styles have nearly equal size, and each bears six to eight pairs of branches. The eight fingers of the terminal coronets diverge nearly in one plane, and are not curved in a zigzag manner, but armed with alternate, slender, recurved hooks, which are larger than in the two preceding species, and geniculate at the base; the distal end of each finger bears a verticil of eight to ten very small divergent teeth, which are not recurved (fig. 9).

_Dimensions._--Length of the shell 2.4, breadth 2.2.

_Habitat._--North Pacific, Station 252, surface.

Genus 736. _Coelodecas_,[352] n. gen.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with ten styles (one odd and four paired styles on each valve).

The genus _Coelodecas_ is closely allied to _Coelographis_, but differs from it in the development of a new pair of styles on each valve. These are placed between the odd nasal and the paired tergal styles, are usually directed laterally, parallel to the frontal axis of the body, and may therefore be called frontal or lateral styles. The total number of coronal styles is therefore ten.

1. _Coelodecas sagittaria_, n. sp. (Pl. 126, figs. 2_a_, 2_b_).

Shell-mantle one and a half times as long as broad; its frontal perimeter pentagonal, with a deep median incision at the base; the two oral sides of the pentagon twice as long as the two lateral sides, and one and a half times as long as the base. Sagittal perimeter ovate; equatorial perimeter subcircular. Nasal odd style of each valve with fourteen to sixteen pairs of branches, one and a half times as long as the paired frontal styles (each with eight to nine pairs), and twice as long as the paired tergal styles (each with four to six pairs of branches). Terminal coronets (on the free distal ends of the styles) richly branched, each with thirty to forty thorny fingers, which bear a conical point with recurved teeth, like an arrow.

_Dimensions._--Length of the shell 3.2, breadth 2.1.

_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms.

2. _Coelodecas decastyla_, n. sp.

Shell-mantle one and a third times as long as broad; its frontal perimeter pentagonal, with a slight incision on the base; the two oral sides of the pentagon as long as the base, and one and a {1756}half times as long as the two lateral sides. Nasal odd style of each valve with ten to twelve pairs of branches, about twice as long as the four paired frontal and tergal styles, each of which bears five or six pairs. Terminal coronets three times forked, each with eight straight, spinulate, slightly divergent fingers, shaped like a human finger.

_Dimensions._--Length of the shell 3.6, breadth 2.7.

_Habitat._--Central Pacific, Station 272, depth 2600 fathoms.

3. _Coelodecas pentagona_, n. sp.

Shell-mantle about as long as broad; its frontal perimeter nearly regular pentagonal, with five equal sides. Nasal odd style of each valve with six to eight pairs of branches scarcely longer than the four paired frontal and tergal styles, each of which is provided with four to six pairs. Terminal coronets irregularly branched, each with twelve to sixteen slender curved fingers, which bear at the distal end a spinulate knob.

_Dimensions._--Length of the shell 2.6, breadth 2.4.

_Habitat._--South Atlantic, Station 332, depth 2200 fathoms.

Genus 737. _Coelostylus_,[353] n. gen.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with twelve styles (two odd and four paired styles on each valve).

The genus _Coelostylus_ is characterised by the possession of twelve coronal styles; it is closely allied to _Coelospathis_, and differs from this in the development of a new pair of styles on each valve. These are placed between the odd nasal and the odd sagittal style of each valve, they are directed forwards, and may therefore be called "pectoral styles."

1. _Coelostylus bisenarius_, n. sp. (Pl. 126, fig. 3_a_, 3_b_).

Shell-mantle one and a third times as long as broad; its frontal perimeter pentagonal, with a deep median incision at the base; the two oral sides of the pentagon about as long as the basal odd side, and half as long as the two lateral sides. Sagittal perimeter (fig. 3_a_) octagonal; the three paired lateral sides of the bilateral octagon about equal, and somewhat shorter than the basal and oral odd sides. Equatorial perimeter rounded square. Nasal odd style of each valve with twelve alternate-cruciate pairs of lateral branches, about twice as long as the two paired pectoral styles (each with four pairs), and the odd sagittal style (with six pairs); the two paired tergal styles bear eight pairs and are longer than the latter, shorter than the nasal style. All styles are more or less curved, divergent, and at the distal end four times forked, bearing a terminal coronet with sixteen spinulate fingers (fig. 3_b_).

_Dimensions._--Length of the shell 4.2, breadth 3.2.

_Habitat._--Indian Ocean (Madagascar), Rabbe, surface.

{1757}2. _Coelostylus flabellatus_, n. sp.

Shell-mantle one and a half times as long as broad, very similar to that of the preceding species. It differs from this mainly in the peculiar form of the twenty-four terminal coronets, which are flabellate and very similar to the terminal branches of _Coelodendrum flabellatum_ (Pl. 121, figs. 5, 6). I formerly supposed, therefore, that both forms belonged to one and the same species. But though I had no complete specimens of the two species, I was afterwards led to the opinion that one and the same peculiar form of terminal branches is here produced by adaptation to similar conditions in two very different genera. Each coronet is a flat flabellum, placed in a meridian plane, and composed of eight pairs of spinulate branches as figured, _loc. cit._, in figs. 5 and 6. The cap-shaped distal end of each finger is armed with eight to twelve recurved teeth.

_Dimensions._--Length of the shell 3.8, breadth 2.6.

_Habitat._--North Pacific, Station 252, surface.

Genus 738. _Coeloplegma_,[354] n. gen.

_Definition._--#Coelographida# with an odd frenulum on each galea and an outer lattice-mantle, armed with fourteen styles (one odd and six paired styles on each valve).

The genus _Coeloplegma_, distinguished by the possession of fourteen coronal styles, is closely allied to _Coelodecas_, but differs from it in the development of a new pair of styles on each valve. These are placed between the odd nasal and the paired frontal styles, are directed forwards, and may therefore be called pectoral styles, corresponding to those of _Coelostylus_.

1. _Coeloplegma murrayanum_, n. sp. (Pl. 127, figs. 1-13.).

Shell-mantle about as long as broad, its frontal perimeter subcircular, or slightly pentagonal, with five convex sides, its sagittal perimeter also nearly circular. Odd nasal style with six to eight, the paired pectoral styles with two or three, lateral styles with three to five, and tergal styles with six to nine pairs of branches. The central capsule constantly contains masses of crystals (figs. 4-7). Terminal coronets (on the free distal ends of the styles) three times furcate, each with eight simple and short fingers. This interesting species, discovered by Dr. John Murray in August 1882, during the expedition of H.M.S. "Triton," in great numbers in the Gulf Stream, off the Færöe Channel, is very variable and connected by numerous transitional forms with the following closely allied species. (Compare the following note.)

_Dimensions._--Length of the shell 1.6 to 2.2, breadth 1.5 to 2.1.

_Habitat._--North Atlantic, Gulf Stream, off the Færöe Channel, in depths between 40 and 200 fathoms, John Murray.

{1758}2. _Coeloplegma tritonis_, n. sp. (Pl. 127, figs. 2-13).

Shell-mantle one and a quarter times as long as broad, its frontal perimeter heptagonal, with seven concave sides (fig. 2), its sagittal perimeter ovate, its zonal perimeter nearly square (fig. 3). Odd nasal style with twelve to fourteen, the paired pectoral styles with three to four, lateral styles with six to eight, and tergal styles with eight to ten pairs of branches. Coronets three times forked, each with eight terminal branches, bearing a small spinulate knob. This remarkable species, in external appearance very different from the preceding, is connected immediately with it by numerous transitional varieties; both species represent the opposite terminal poles of a long series of "Darwinian metamorphic forms." If only the two specimens, figured in Pl. 127, figs. 1 and 2, were known, every one would distinguish them as two widely different species. But the careful comparison of numerous intermediate forms demonstrates that there is no "missing link" in this long and remarkable chain. The careful comparative study of these very variable and most highly developed Coelographida may be regarded as a strong argument for the theory of descent, and explains the true "origin of species."

_Dimensions._--Length of the shell 1.8 to 2.5, breadth 1.5 to 2.1.

_Habitat._--North Atlantic, Gulf Stream, off the Færöe Channel, in depths between 40 and 200 fathoms, John Murray.

3. _Coeloplegma tetradecastylum_, n. sp.

Shell-mantle one and a third times as long as broad, its frontal perimeter heptagonal, with seven concave sides. Similar to the preceding species, differs from it mainly in the prolonged nasal style, which bears sixteen to eighteen pairs of branches, and is about three times as long as each of the six paired styles, each of which bears five to six pairs of branches. Coronets three times forked, each with eight terminal branches, armed with scattered spines, and bearing a knob with three recurved hooks.

_Dimensions._--Length of the shell 3.2, breadth 2.4.

_Habitat._--Tropical Atlantic, Stations 335 to 342, surface.

4. _Coeloplegma atlanticum_, n. sp.

Shell-mantle one and a half times as long as broad, its frontal perimeter ovate. Similar to _Coeloplegma murrayanum_ (Pl. 127, fig. 1), differs from it in the different length of the styles; the nasal odd style (with eighteen to twenty pairs of branches) is about twice as long as the lateral styles (with ten to twelve pairs), and three times as long as the pectoral and tergal styles (with six to eight pairs). Coronets four times forked, each with sixteen terminal branches, armed with recurved spines, and bearing a cross of four curved hooks.

_Dimensions._--Length of the shell 2.5, breadth 1.7.

_Habitat._--South Atlantic, Station 318, depth 2040 fathoms.

{1759}Genus 739. _Coelagalma_,[355] n. gen.

_Definition._--#Coelographida# with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with sixteen styles (two odd and six paired styles on each valve).

The genus _Coelagalma_ represents the highest degree of development among the Coelographida, and exhibits the maximum number of coronal styles in this family, viz., sixteen (eight on each valve). Two of these are odd (as in _Coelospathis_ and _Coelostylus_), viz., the longitudinal anterior nasal style, and the horizontal sagittal style. The six others are paired (as in _Coeloplegma_), viz., two anterior or pectoral, two lateral or frontal, and two posterior or tergal styles. Since _Coelagalma_ in this highest developed armature exceeds all the other Coeloplegmida, and exhibits at the same time the utmost complexity in structural detail, it may be regarded as one of the most perfect forms not among the PHÆODARIA only, but among all Radiolaria.

1. _Coelagalma mirabile_, n. sp. (Pl. 126, figs. 4, 4_a_).

Shell-mantle one and a half times as long as broad, its frontal perimeter (fig. 4_a_) heptagonal, with seven concave sides, its sagittal perimeter octagonal, its equatorial perimeter hexagonal (fig. 4_b_), the corners of the polygons are marked by the sixteen prominent styles. Nasal odd style longer; and sagittal odd style shorter, than the six paired styles of each valve; the two pectoral styles are directed forwards, the two lateral styles are nearly opposed in the horizontal frontal diameter, while the two shorter tergal styles are directed backwards. The terminal coronets (at the distal ends of the sixteen styles) are four times forked, with sixteen equal spinulate fingers, each finger at the distal end with eight recurved teeth. The entire surface of the bivalved latticed mantle is densely studded with hundreds of most elegant anchor-pencils, so that the external appearance of this beautiful species becomes one of the most wonderful among Radiolaria.

_Dimensions._--Length of the shell 5.4, breadth 3.6.

_Habitat._--Central area of the Pacific, Station 271, depth 2425 fathoms.

{1760}NOTE ON THE DIMENSIONS AND MEASUREMENTS OF THE DESCRIBED SPECIES OF RADIOLARIA.

All the dimensions of the species of Radiolaria described in the present work are given in millimetres. In the majority of the species the dimensions of only a single observed specimen have been measured by the micrometer, and usually only the most important proportions have been recorded. But since the outlines of nearly all the species figured (with very few exceptions) have been drawn by the camera lucida, and therefore usually are almost perfectly exact, and since the excellent artist, Mr. Adolph Giltsch, has executed the lithographic plates with the greatest accuracy, having examined the objects themselves under the microscope, it is very easy to determine the dimensions of all the separate parts by comparative measurement. In very many of the species described (perhaps nine hundred or a thousand) several specimens of each species (usually three or four) have been measured comparatively, and the dimensions recorded are taken as averages. A very important contribution to the general conception of the proportions, and especially to the important question of the constancy of the dimensions, has been given by my honoured friend Dr. Reinhold Teuscher of Jena. This excellent observer, to whom I am indebted for much and important co-operation in my Radiolarian work, has instituted at my request a long series of measurements, with the view of comparing the dimensions (of the entire skeleton as well as of its individual parts) in numerous (usually twenty or thirty) specimens of one and the same species. About three hundred species of very different groups (mainly #Sphæroidea#, #Discoidea#, #Spyroidea#, and #Cyrtoidea#) have been measured in this manner, and the general survey of the results obtained (about eight thousand measurements were recorded) has enabled me to form a good opinion of the constancy and variability of the dimensions in the individual species. The general result is, that they are not absolutely constant in any given case, but that each species (of which many specimens have been carefully compared) exhibits a certain degree of variability in all its proportions. The general meaning of "species," therefore, is in the unicellular Radiolaria the same as in all other organisms, and its development follows the same laws as are so accurately explained by Charles Darwin in his Origin of Species.

ADDENDA.

I. _List of Twenty-two Deep-Sea Radiolarians from the Banda Sea._

P. Harting (L. N. 18) published in 1863 the description of 14 SPUMELLARIA and 8 NASSELLARIA, taken in depths between 900 and 4000 fathoms, in the Banda Sea. The figures of them are, however, for the most part not complete enough. The names are the following:--

I. SPUMELLARIA.

1. _Haliomma nitidum_, figs. 13, 14 = _Heliodiscus_?
2. _Haliomma gracile_, fig. 15 = _Acanthosphæra_?
3. _Haliomma lens_, fig. 16 = _Stylodiscus_?
4. _Haliomma pyriforme_, fig. 17 = _Cenellipsis_?
5. _Haliomma scutum_, fig. 18 = _Botryocella_?
6. _Haliomma polyacanthum_, fig. 40 = _Druppocarpus_?
7. _Haliomma inerme_, fig. 41 = _Thecosphæra_?
8. _Haliomma oblongum_, fig. 42 = _Druppula_?
9. _Haliomma amphiaspis_, fig. 43 = _Monozonium_?
10. _Tetrapyle polyacantha_, fig. 44 = _Larcarium_?
11. _Flustrella cyclica_, fig. 19 = _Porodiscus_.
12. _Flustrella micromma_, fig. 47 = _Porodiscus_.
13. _Rhopalastrum bandaicum_, fig. 45 = _Dictyastrum_.
14. _Lithocyclia reticulata_, fig. 20 = _Spongodiscus_?

II. NASSELLARIA.

15. _Lithocircus annulus_, fig. 50 = _Lithocircus_.
16. _Acanthodesmia arcuata_, fig. 25 = _Zygostephanus_.
17. _Acanthodesmia inermis_, fig. 26 = _Dictyospyris_?
18. _Cladospyris moluccana_, fig. 48 = _Cyphonium_?
19. _Podocyrtis brevipes_, fig. 24 = _Podocyrtis_.
20. _Podocyrtis micracantha_, fig. 49 = _Podocampe_?
21. _Lithocampe corbula_, fig. 21 = _Lithomitra_.
22. _Lithocampe sinuosa_, fig. 22 = _Lithocampe_?

II. _List of Fossil Radiolaria (probably Jurassic) found in the "Diaspri
della Toscana," and described in 1880 by Dante Pantanelli_ (L. N. 36).
(_Compare_ § 243, _Note_ B, p. clxviii).

The figures are too small and too incomplete for certain determination.

I. SPUMELLARIA.

1. _Ethmosphæra minuta_.
2. _Ethmosphæra vulgaris_.
3. _Ethmosphæra siphonophora_.
4. _Heliosphæra echinoidites_.
5. _Rhaphidococcus lusianensis_.
6. _Heliodiscus simplex_.
7. _Histiastrum lusianense_.
8. _Trematodiscus soritoides_.
9. _Euchitonia muellerites_.
10. _Euchitonia amoena_.
11. _Euchitonia clathrata_.
12. _Euchitonia crevolensis_.
13. _Euchitonia grandis_.
14. _Euchitonia dubia_.

II. NASSELLARIA.

15. _Lithocircus haeckelii_.
16. _Lithocircus truncatus_.
17. _Lithocircus rhombus_.
18. _Cornutella pseudoprofunda_.
19. _Cornutella pseudoclathrata_.
20. _Lithopera ovata_.
21. _Lithopera elongata_.
22. _Polystichia ehrenbergii_.
23. _Polystichia haeckelii_.
24. _Polystichia muelleri_.
25. _Urocyrtis emmæ_.
26. _Urocyrtis amaliæ_.
27. _Urocyrtis stephanii_.
28. _Adelocyrtis cometa_.
29. _Adelocyrtis pala_.
30. _Adelocyrtis spinosa_.

ERRATA.

Page 23, line 3 from top, _add_ "Compare also _Myxobrachia cienkowski_,
Wagner, 1872, L. N. 23."

Page 40, bottom line, _add_ "The two following species are incompletely
known:--_Sphærozoum orientale_, Dana, 1863, _Ann. and Mag. Nat. Hist._,
vol. xii. p. 54. _Sphærozoum sanderi_, Doenitz, 1871, L. N. 60, p. 71."

Page 65, line 15 from top, _add_ "_Cenosphæra radiata_, Zittel, 1876 (L.
N. 29, p. 84, Taf. ii. figs. 7, 8), a fossil Cretaceous species, is
closely allied to _Cenosphæra compacta_."

Page 84, line 17 from top, _add_ "_Caryosphæra polysphærica_, Bütschli,
1882 (L. N. 41, Taf. xxiii. fig. 12) is probably a _Cromyosphæra_ (fossil
in Barbados)."

Page 95, line 11 from top, _add_ "_Dermatosphæra_, Ehrenberg, is a
_Collosphæra_ with small pores (compare L. N. 16, p. 533)."

Page 97, line 8 from foot, _for_ "xxiv." _read_ "xxxiv."

Page 122, line 14 from foot, _for_ "_Spongolonche_" _read_
"_Spongolonchis_."

Page 149, lines 1, 4, 6 and 12 from top, _for_ "_Spongolonche_" _read_
"_Spongolonchis_."

Page 149, line 2 from foot, _for_ "_Spongolonche_" _read_
"_Spongolonchis_ ([Greek: spongos], [Greek: lonchis])."

Page 172, line 4 from foot, _add_ Synonym "? _Haliphormis hexacantha_,
Ehrenberg, 1872, L. N. 24, Taf. x. fig. 6."

Page 216, line 11 from foot, _add_ "Taf. xiii."

Page 308, line 4 from top, _add_ "Compare _Haliomma oblongum_, Harting,
1863, L. N. 18, p. 15, pl. 2, fig. 42."

Page 326, line 14 from foot, _for_ "1872" _read_ "1875."

Page 461, line 12 from foot, _delete_ "H."

Page 463, line 10 from top, _add_ "Indian Ocean, Cocos Islands, Rabbe."

Page 492, bottom line, _add_ "_Porodiscus haeckelii_ = _Trematodiscus
haeckelii_, Bütschli, 1882, L. N. 41, Taf. xxiv. figs. 5_a_, 5_b_."

Page 509, bottom line, _add_ "_Stylodictya haeckelii_, Zittel, 1876, L.
N. 29, p. 85, Taf. ii. fig. 9, is a fossil Cretaceous species, related to
_Stylodictya multispina_."

Page 534, line 11 from foot, _add_ "Indian Ocean, Cocos Islands (Rabbe).
Also in the Central Pacific, Station 267."

Page 584, line 12 from top, _for_ "1872" _read_ "1875."

Page 586, line 7 from foot, _add_ "_Spongotrochus ehrenbergii_, Bütschli,
1882, L. N. 41, Taf. xxvi. figs. 1_a_, 1_b_."

Page 633, bottom line, _add_ "_Monozonium hartingii_ = _Haliomma
amphiaspis_, Harting, 1863 (L. N. 18, p. 15, pl. 2, fig. 43)."

Page 763, line 8 from top, _add_ "Pl. 132, fig. 11."

Page 784, line 16 from top, _for_ "vi." _read_ "xvi."

Page 802, line 14 from bottom, _after_ "11_a_" _insert_ "11_c_."

Page 839, line 13 from top, _for_ "95" _read_ "135."

Page 841, line 8 from foot, _after_ "figs." _insert_ "2."

Page 842, line 13 from top, _add_ "_Haliomma ligurinum_, J. Müller (=
_Haliommatidium ligurinum_, Haeckel, L. N. 16, p. 423) seems to be
closely allied to the preceding."

Page 889, line 6 from top, _add_ "_Cricoidea_, Bütschli, 1882 (L. N. 40,
p. 537) = NASSELLARIA."

Page 951, line 9 from foot, _add_ "Fossil in Barbados."

Page 952, line 2 from foot, _add_ "Fossil in Barbados."

Page 966, line 10 from top, _add_ "Fossil in Barbados."

Page 981, line 19 from top, _add_ "Fossil in Barbados."

Page 1037, line 8 from top, _add_ "Pl. 85, fig. 2."

Page 1081, line 12 from foot, _add_ "Pl. 95, fig. 15."

Page 1158, line 10 from foot, _for_ "516. _Cyrtophormis_" _read_ "516.
_Cystophormis_."

Page 1165, lines 8, 11 and 15 from foot, _for "Cyrtophormis" read
"Cystophormis_."

Page 1165, bottom line, _read_ "_Cystophormis_ = bladder-basket; [Greek:
kystê], [Greek: phormis]."

Page 1166, lines 1, 7 and 13 from top, _for_ "_Cyrtophormis_" _read_
"_Cystophormis_."

Page 1250, line 7 from top, _for_ "_Dictyoprora_" _read_ "_Dictyoprona_."

Page 1251, line 11 from top, _add_ "Pl. 62, fig. 3."

Page 1356, line 9 from foot, _add_ "Pl. 68, fig. 14."

Page 1384, line 2 from foot, _for_ "_Calocycloma_" _read_
"_Calocyclura_."

Page 1411, first line, _add_ "Pl. 68, fig. 15."

Page 1560, line 2 from top, _add_ "_Dictyocha trigona_, Zittel, 1876 (L.
N. 29, p. 83, Taf. ii. fig. 6), is an interesting Cretaceous species,
perhaps a variety of _Dictyocha triommata_."

Page 1615, line 6 from top, _insert_ "n. sp." _after_ "_scenophora_."

Page 1653, line 7 from top, _add_ "John Murray, 1876, L. N. 27, pl. 24,
fig. 2."

Page 1706, line 7 from foot, _add_ "John Murray, 1876, L. N. 27, pl. 24,
fig. 4."

Page 1752, line 4 from bottom, _for_ "figs. 1_a_-1_d_" _read_ "figs.
1_a_-1_c_."

Page 1757, line 14 from bottom, _for_ "fig. 1" _read_ "figs. 1-13."

Page 1759, line 14 from bottom _for_ "figs. 4_a_, 4_b_" read "figs. 4,
4_a_."

INDEX.

Synonyms are printed in _Italics_; names of Families, Orders, &c., in
CAPITALS.