Chapter L: ANATIFERA. Linnæus. Systema Naturæ, 1767

ANATIFA vel ANATIFERA vel PENTALASMIS lævis[24], plerumque
auctorum.

---- ENGONATA (!).[25] _Conrad._ Journal Acad. Nat. Sc.
Philadelphia, vol. vii, 1837, p. 262, Pl. xx, fig. 15.

---- DENTATA (var.) _Brugière._ Encyclop. Meth. (des Vers), 1789.

PENTALASMIS DENTATUS (var.) _Brown._ Illust. Conch., Pl. lii, fig.
5.

ANATIFA . . . . . _Martin St. Ange._ Mem. sur l’organisation des
Cirripedes, 1835.

[24] As this, though the commonest species, has never been
defined, I give only a few synonyms and references, it being
quite impossible to distinguish, in any published description,
this species from _A. Hillii_ of Leach; this latter species I
recognise under this name only from having authentic specimens
from the British Museum, as Leach overlooked every one of the
real diagnostic characters.

[25] I have used, in conformity with botanists, the mark of
interjection, to show that I have seen an authentic specimen.

_L. valvis aut lævibus aut delicate striatis: è duobus scutis, dextro solùm dente interno umbonali instructo; pedunculi parte superiore fuscâ._

Valves smooth, or delicately striated. Right-hand scutum alone furnished with an internal umbonal tooth: uppermost part of peduncle dark-coloured.

Filaments, two on each side.

Var. (_a_). Fig. 1. Scuta and terga with one or more diagonal lines of dark greenish-brown, square, slightly depressed marks.

Var. (_b_). (Fig. 1 _b._) Carina strongly barbed.

Extremely common; attached to floating timber, vessels,
sea-weed, bottles, &c., and to each other, in the Atlantic
Ocean, Mediterranean, West Indies, Indian Ocean, Philippine
Archipelago, Sandwich Islands, Bass’s Straits, Van Diemen’s
Land.

_General Appearance._--Valves white, more or less translucent and thick, with a tinge of blueish-grey, from the underlying corium; sometimes brownish cream-coloured, rarely with a tint of purple. Surfaces smooth, with traces of very fine lines radiating from the umbones, sometimes rather plain on the basal part of the scuta. Length in proportion to the breadth of the capitulum variable, owing to the varying degree to which the scuta and terga have their apices produced. _Scuta_ with the occludent margin either considerably curved or nearly straight. The internal tooth of the right-hand scutum, close to the umbo, varies in size and form, being either pointed, square, or obliquely truncated on either side, or it has a notch on the summit; internal basal rim of the scuta either plainly developed or nearly absent. In many specimens (Pl. I, fig. 1), on the scuta, or on the scuta and terga, (and sometimes more on one side of the individual than on the other,) a nearly straight line, running diagonally across the capitulum, of slight, quadrilateral depressions, of a dirty greenish colour, with the edges blending away, is either conspicuously developed, or can only just be discerned. These marks increase in size from the umbones to the margins of the valves. There are sometimes two or even three rows on the scuta. They are formed by the retention of a portion of the chitine membrane, which is cast off the rest of the surface; the margins of the valves are occasionally notched slightly on the line of marks; there is no difference along this line in the underlying corium. Specimens both with and without a barbed carina are thus characterised. _Carina_; the interspace between the carina and the scuta and terga is not wide. The carina exteriorly, is either convex and smooth, or furnished with knobs or with extremely sharp, long teeth (Pl. I, fig. 1 _b_); small specimens, with the capitulum under half an inch in length, are generally most strongly barbed.[26] Apex more or less acuminated; width and thickness variable; sides strongly furrowed. Fork (fig. 1 _a_) generally less wide than the widest upper part of the valve, with the two prongs diverging from each other at less than a right angle; their sharpness and precise form variable; rim between them reflexed (figs. 1 _a_ and _b_), making a slight notch behind. _Peduncle_ smooth, wrinkled, length in proportion to that of the capitulum varying, from barely equalling it, to six or seven times as long. I have noticed a specimen including mature ova, with a capitulum under half an inch long.

[26] Mr. W. Thompson found that 15 specimens, out of about 200,
attached to a vessel which came from New Orleans into Belfast,
had their carinas barbed.

_Filamentary Appendages_;--never more than two on each side, with sometimes only one developed; of variable length; one seated on the flank of the prosoma, under the first cirrus; the second close under the basal articulation of this cirrus, on the posterior face of a slight swelling: these appendages correspond with _g_ and _h_ in Fig. 4, Pl. IX.

_Mouth._--Mandibles (Pl. IX, fig. 5), with, as usual, five teeth, all pointing downwards. Maxillæ (Pl. IX, fig. 9), with the lower step of variable width compared to the two upper steps. _Cirri_; posterior cirri with segments (fig. 26) bearing six pair of spines; intermediate fine spines rather long; first cirrus, anterior ramus longer by only about two segments than the posterior ramus; second cirrus with anterior ramus, with very broad transverse rows of bristles; spine-bearing surfaces considerably protuberant; caudal prominences smooth, rounded.

_Size._--The largest specimen which I have seen had a capitulum two inches in length; the longest, including the peduncle, was sixteen inches.

_Colours._--Calcareous valves already described. Edges of the orifice bright scarlet orange; basal edges of the scuta, and sometimes of all the valves, with a torn border of orange membrane. Interspaces between the valves dull orange-brown. Peduncle darkish purplish-brown, with the lower part sometimes pale; chitine membrane itself tinted orange; in young specimens, peduncle pale, the colour first appearing in the uppermost part, close under the capitulum; this upper part is often darker than the other parts, and never orange-coloured, as in _L. Hillii_ and _L. anserifera_. _Sack_ internally dark purplish lead-colour, sometimes with a tinge of orange, darkest under the growing edges of the valves; body of animal pale purplish lead-colour. The four posterior cirri blackish purple; the second, and often the third cirrus, appear as if the colour had been laterally abraded off; these latter cirri have sometimes a tinge of orange. In very young specimens, the cirri are only barred with purple. The ova and the contents of the ovarian tubes are of a beautiful azure blue, becoming yellow in spirits.

In museums a vast amount of difference is seen in the colours of this species, caused by the method of preparation: if dried without having been in spirits, and subsequently kept dry, the orange tint round the orifice is preserved; if kept long in spirits, this is quite lost; but sometimes in specimens in spirits the colour of the membrane of peduncle is preserved and rendered pinker. The colours of the sack and animal are either quite discharged or rendered extremely dark. The valves themselves also often become more opaque. In some specimens well preserved in spirits, the sack and cirri were purplish-brown or lead-colour, tinted with dirty green, or orange, or bright yellow, or brick-red.

_General Remarks._--From the foregoing description it will be seen how extremely variable almost every part of this species is. I find, in the British Museum, ten distinct specific names given by Dr. Leach to different varieties, or rather to different specimens, for some of them are undistinguishable. A specimen from the Sandwich Islands, sent by Mr. Conrad to Mr. Cuming, is marked _A. engonata_.

In looking over a large collection of specimens in a museum, the most distinctive characters appear at first to be the colours, the dentation or barbed condition of the carina, the row of square marks on the scuta and terga, and the more or less produced form of the whole capitulum: all these characters are absolutely worthless as distinctive characters, and blend into each other. In a fresh condition, the colours of this species, and of _L. anserifera_ and _L. Hillii_ are surprisingly alike, though in _L. anatifera_ alone, the uppermost part of the peduncle is dark. As far as I have seen, the smoothness of the valves, together with the presence of a tooth beneath the umbo, on the right-hand scutum, and its entire absence on the left side, (in other species it is smaller on this, than on the right-hand side,) is an unfailing diagnostic mark. I believe this species is always attached to floating objects, though there are some very young specimens in the British Museum, collected by Sir G. Grey, adhering to sandstone, but this may have been buoyed up by some large sea-weed. Mr. Peach has given me the particulars of two instances, in which, after gales of wind, this species, of nearly full size, adhering to _apparently_ freshly broken-off Laminariæ, has been cast upon the coast of England and Scotland.

2. LEPAS HILLII. (Pl. I, fig. 2).

ANATIFA vel PENTALASMIS LÆVIS (!) plerumque auctorum.

PENTALASMIS HILLII (!). _Leach._ Tuckey’s Congo Expedit. p. 413,
1818.

---- CHELONIÆ (!) Ib. Ib.

ANATIFA TRICOLOR (?). _Quoy_ et _Gaimard_. Ann. des Sc. Nat., 1st
series, tom. x, 1827, Pl. vii, fig. 7, et Voyage de
l’Astrolabe, Pl. xciii, fig. 4.

---- SUBSTRIATA (!). _Conrad._ Journal Acad. Nat. Sc.,
Philadelphia, vol. vii, 1837, p. 262, Pl. xx, fig. 14.

_L. valvis lævibus; scutorum dentibus internis umbonalibus nullis; carinâ à cæteris valvis, furcâ etiam a scutorum basali margine, paululum distante; pedunculi parte superiore aut pallidâ aut aurantiacâ._

Valves smooth; scuta destitute of internal umbonal teeth; carina standing a little separate from the other valves, with the fork not close to the basal margin of the scuta; uppermost part of peduncle either pale or orange-coloured.

Filaments three on each side.

Extremely common; attached to ships’ bottoms, from all parts of
the world; on floating timber; associated with _L. anatifera_
and _L. anserifera_. Mediterranean. Attached to turtles, in the
Atlantic, lat. 30° north. West Indies. Falkland Islands. “South
Seas,” collected by A. Menzies. Port Stephen, Australia.

_General Appearance._--Capitulum laterally flat; length varies in proportion to the breadth; valves white, somewhat translucent, moderately thick, very smooth, but with faint traces of radiating lines; in some varieties, surface rather irregular along the zones of growth. _Scuta_ without any internal teeth, and with scarcely any trace of the internal basal rim; upper angle little acuminated; the occludent margins of the two scuta stand rather separate from each other, showing a wide space of corium between them: these margins are arched and protuberant, but with the lower part a little hollowed out; basal margin a little curved. In one specimen alone, I saw a trace of a diagonal line of square coloured marks, like those common in _L. anatifera_. _Terga_ rather broad, with the basal angle not much acuminated. The degree of prominence and outline of the double occludent margin varies very much. _Carina_, separated by a rather wide space from the scuta and terga; of very varying shape, the upper part not much acuminated, generally very flat, sometimes exteriorly marked by a central depressed line; never barbed; occasionally, (in a specimen from Australia,) middle part so wide as almost to become spoon-shaped; on the other hand occasionally of nearly the same width throughout; somewhat constricted above the fork. Fork deeply embedded as usual; situated, in fresh specimens, a little way beneath the basal margins of the scuta, instead of touching them, as in the other species; forks of varying width, not so abruptly inflected as in many species; sometimes much narrower than the upper widest part of the valve, sometimes nearly twice as wide; prongs of fork not very sharp, diverging at about a right angle, with the rim between them reflexed. The apex of the carina extends up between the terga for barely half their length, instead of up fully three fourths of their length, as in _L. anatifera_.

The chitine membrane at the base of the capitulum, especially at the anterior and posterior ends, is covered with beautiful, little, embedded, yellowish beads, about 3/2000th of an inch in diameter; above this, on each side of the carina, there is a space with similar but smaller little spheres, and still higher up still minuter ones; others occur on different parts of the capitulum; these spaces are seen to be distinctly separated from each other, and present a beautiful appearance under a high power.

_Peduncle_, as long as, or rather longer than, the capitulum: in one set of specimens, however, it was thrice or four times as long as the capitulum. The peduncle, in some specimens, was conspicuously covered with transverse plates of yellowish hard chitine.

_Filamentary Appendages._--Three on each side; one on the flank of the prosoma, with a pair beneath the basal articulation of the first cirrus; relative lengths various, but the posterior filament of the pair under the cirrus, is the shortest. _Mouth_; palpi not much acuminated; maxillæ step-formed, but with the upper or first step in some specimens indistinct, or forming a curve. _Cirri_; the segments of the first cirrus and of the posterior arm of the second cirrus are highly protuberant, the protuberances sometimes equalling half the thickness of the segments themselves. Caudal appendages smooth, rounded.

_Size._--The largest specimen which I have seen, in the collection of Mr. Cuming, had a capitulum 1-1/10th of an inch long, and 1-1/4 wide; therefore not quite equalling in size the largest specimens of _L. anatifera_.

_Colours._--When fresh, valves blueish-grey from the underlying corium, edges of all the valves and round the orifice, and round the top of the peduncle, bright orange-yellow, passing into the finest scarlet, and varying slightly in tint in different specimens. Space between the carina and the other valves, and between the occludent margins of the scuta, rich purplish-brown; peduncle either pale or purplish-brown, or only clouded on the sides with the same. In young specimens, peduncle nearly colourless; and in those under a quarter of an inch long in the capitulum, the top of the peduncle has not acquired its orange tint. Sack pale, leaden-purple, body the same, but paler and more reddish; cirri (but only the tips of first pair) tinted with fine golden orange. Immature ova in peduncle beautiful blue. After being long kept in spirits, the colours are changed, weakened, or discharged, as in _L. anatifera_ and _L. anserifera_, and the valves become opaque. In some long-kept specimens the corium everywhere had become pale brown; more usually it assumes a dirty purplish lead-colour.

_Monstrous Variety._--Amongst a set of ordinary specimens from a ship from Genoa, sent me by Mr. Stutchbury, there were three, one full-grown and two very young, with the whole capitulum, (and likewise with the scuta and terga taken separately,) not above half the usual length in proportion to the breadth. Neither the colours nor animal in this variety presented any difference.

_General Remarks._--This species is almost universally confounded with _L. anatifera_. Quoy and Gaimard, however, appear to have distinguished it, under the name of _A. tricolor_, from its colours. Leach named it accidentally, for he specifies not one distinctive character, and besides his two published names, he has appended two other names to specimens in the British Museum. A specimen, from the Sandwich Islands, sent by Mr. Conrad to Mr. Cuming, is marked _A. substriata_. In a dry state, from the shrinking of the membranes, and consequent approach of the carina to the other valves, and of the fork to the basal margin of the scuta, it is most difficult to distinguish this species, though so decidedly distinct, from _L. anatifera_; the absence, however, of a tooth on the under side of the right-hand scutum is at once characteristic. Even in specimens kept in spirits, in which there has been no shrinking, but in which the colours have changed, and taking into account the variation in the carina and upper part of the terga, this species is not always readily distinguished from _L. anatifera_, without opening the valves and looking for the right-hand tooth of the latter. In fresh specimens, the orange ring at the top of the peduncle, and the broad purplish interspace between the carina and other valves, are characteristic. In all states, the filamentary appendages offer a good character.

3. LEPAS ANSERIFERA. Pl. I, fig. 4.