_Pedicels_, as in the other species.
_Caudal Appendages_, lost.
This species comes very close, as far as the characters derived from the trophi serve, to the _L. truncata_, though readily distinguished from that species by the shape of the valves. On the other hand, the capitulum of this species is distinguished with difficulty from that of _L. Nicobarica_ and _L. cauta_; no doubt this difficulty is much enhanced by the rostrum and peduncle having been lost.
5. LITHOTRYA TRUNCATA. Pl. IX, fig. 1.
ANATIFA TRUNCATA. _Quoy_ et _Gaimard_. Voyage de l"Astrolabe, Pl.
xciii, figs. 12 to 15, 1834.
_L. scutis in profundam tergorum plicam insertis: carinae crista centrali prominente et rotundata in parte superiore: rostro et lateribus rudimentalibus, carinae lat.i.tudinis quindecimam fere partem aequantibus._
Scuta locked into a deep fold in the terga: carina with a prominent central rounded ridge in the upper part: rostrum and latera rudimentary, about 1/15th of the width of the carina.
Mandibles, with nearly three times as many pectinations between the first and second teeth, as between the second and third teeth; distance between the tips of the first and second teeth equal to that between the tip of the second tooth and inferior angle. Maxillae widely notched, with the inferior part forming two prominences. Caudal appendages shorter than, or barely exceeding in length, the pedicels of the sixth cirrus.
Friendly Archipelago, Mus. Paris; Philippine Archipelago, Mus.
c.u.ming; imbedded in coral rock.
Capitulum rather thick, with the five main valves having their free apices, diverging and truncated. The upper and old layers of sh.e.l.l do not here scale off so readily as in many of the foregoing species; and hence an unusually large proportional length of each valve projects freely above the sack; and the valves are of unusual thickness. The capitulum is very nearly as wide at its summit as at its base, owing to the divergence of the apices of the valves. The scuta and terga are articulated together by a conspicuous fold, which, when seen from vertically above, (Pl. IX, fig. 1 _a"_,) appears like a deep wedge-formed notch in the terga. On the exterior surfaces of the valves, the teeth on the successive rims are approximate; on the inner surfaces, the rims are covered by strong yellow membrane, which is generally fringed with small h.o.r.n.y spines.
_Scuta_, exterior surface convex, sub-triangular, with the apex truncated: seen vertically from above, there is a small rectangular indentation or fold which receives the projecting scutal margin of the terga. The inner growing or corium-covered surface (fig. 1 _b_, _b"_) is triangular, with its tergal margin _largely_ hollowed out. Along the occludent margin there is a slight ridge, which terminates at the rostral angle, in both the right and left-hand valves, in a rounded, k.n.o.b-like, roughened tooth. The lower part of the tergal margin is slightly inflected and roughened, where it meets the corresponding lower part of the scutal margin of the terga. There is a deep pit for the adductor muscle. The interior surface of the valve above this pit is faintly-coloured purple. The inner surfaces of both scuta and terga, are roughened with little points.
_Terga_, seen externally, are almost quadrilateral (owing to the apex being truncated), with the free margin facing the scutum, arched. Seen vertically from above, each shows a deep fold, which receives the lower part of the tergal margin of the scutum. In the foregoing species, a prominent ridge runs down the exterior surface of the terga from the apex to the basal angle, against which ridge, the margin of the overlapping scuta abuts: here this ridge, instead of projecting straight out, is oblique or folded over, and thus forms a furrow, receiving the margin of the scuta. The interior growing surface of the tergum (fig. 1 _b"_, _c_), presents so irregular a figure, that it can hardly be described; in area it quite equals the scuta; it is slightly concave; at the upper point of the carinal margin, there is a large, rounded, protuberant, roughened k.n.o.b, which corresponds with a small k.n.o.b on each side of the inner face of the carina; these k.n.o.bs seem firmly united together by membrane. The scutal margin of the terga, in the upper part, forms a shoulder, largely projecting over the scuta; on its lower part, there is a small roughened projection. The occludent margin is arched and protuberant, with a slight fold above the k.n.o.b on the carinal margin, just mentioned: this fold is caused by the protuberance of the central internal ridge of the carina, but is so small, that when the capitulum is seen from vertically above, it can hardly be distinguished.
Finally, the basal half of the carinal margin, runs in the same line with the basal margin of the scuta.
_Carina_, moderately large; seen externally, the surface presents an elongated triangle, with the apex truncated; on the internal face (fig.
1 _b"_, _d_) of the free part, there is (instead of being concave as is usual) a great central ridge, which projects between the diverging apices of the terga, as may be seen from vertically above; hence the thickness of the upper part of the carina, in a longitudinal plane, almost equals its breadth. The edge of this ridge is rounded. The inner or growing surface of the carina is tinted purple, and lies in a plane, oblique to the longer axis of the valve; it is triangular, with the apex cut off, and the basal margin rounded and protuberant; it is not concave. There is a central raised line or slight ridge on this inner surface, and on each side in the upper part there is a small, white, roughened k.n.o.b, corresponding with the similar k.n.o.bs on the carinal margins of the terga.
_Rostrum_ (fig. 1 _b"_, _a_), rudimentary; in one specimen it was about 1/50th of an inch in width; it is either as wide, or only half as wide, as the subjacent scale on the peduncle.
_Latera_, rudimentary, placed between the edges of the carina and the terga; rather smaller than the rostrum; almost cylindrical, slightly flattened, enlarged at each zone of growth, with one or two sharp teeth or spines on both faces; imperfectly calcified; in width barely 1/15th part of the carina.
_Peduncle_, short; the scales alone in the uppermost whorl are plainly toothed; they are transversely elongated, and almost quadrangular, and are nearly twice as large as those in the second whorl. Beneath this second whorl, there are two or three whorls, with scales, graduated in size; and the rest of the peduncle is covered by rather distantly scattered, minute, rounded or acutely pointed scales: the pointed scales are directed upwards, and are best developed under the carina. The basal calcareous cup, judging from two specimens, is thin, and not much developed.
_Size and Colour._--The largest specimen was nearly 6/10ths of an inch across its capitulum. The calcareous valves are dirty white. The sack is (after having been long kept in spirits) pale coloured, excepting a small purple s.p.a.ce, between the scuta and another over the carina. The three posterior segments of the thorax and portions under the second and third cirri, the trophi, the pedicels and the anterior faces of the segments (especially of the basal segments in the second and third cirri), and a spot on their dorsal surfaces, and the p.e.n.i.s are all coloured dark purplish-black. The prosoma is pale coloured.
_Mouth._--Crest of labrum with a row of bead-like teeth and hairs.
_Palpi_ bluntly pointed, with neither margin hollowed out.
_Mandibles_, with eight pectinations between the first and second main teeth, and three between the second and third teeth; inferior angle coa.r.s.ely pectinated, with a central spine much longer than the others; the distance between the tips of the first and second main teeth, is about equal to that between the tip of the second tooth and of the inferior angle.
_Maxillae._--Under the two upper long spines (a.s.sociated with some smaller ones), there is a slight and wide hollow; and the whole inferior edge obscurely forms two blunt points, with the spines on the lower projection smaller than the upper spines.
_Outer Maxillae_, considerably concave in front, with the spines almost discontinuous in the middle part.
_Cirri._--First pair rather far separated from the second pair. The segments of the three posterior cirri bear three or four pairs of main spines, and are otherwise characterised like the foregoing species.
_First cirrus_, with its anterior ramus much thicker than the posterior ramus, and of nearly equal length; all the segments, except the two terminal ones, thickly clothed with serrated spines. _Second cirrus_ considerably shorter than the third cirrus: anterior ramus with the seven basal segments very protuberant, and paved with bristles, and the four terminal ones on the usual structure; posterior ramus, with the five basal segments paved (but much less thickly than in the anterior ramus), and the nine terminal ones on the usual structure. _Third cirrus_, the anterior ramus, with the five basal segments, thick and paved, and eleven terminal segments on the usual structure: posterior ramus, with one basal segment paved, and sixteen other segments on the usual structure. In the posterior rami, however, of both the second and third cirri, it is difficult to draw any distinct line between the paved segments and the others.
_Caudal Appendages_, short, either just exceeding in length the pedicels of the sixth cirrus, or equalling only the lower segment: segments flattened, cylindrical, six in number, there being, in the same individual, twenty-one segments in both rami of the sixth cirrus.
6. LITHOTRYA VALENTIANA. Pl. VIII, fig. 5.
CONCHOTRYA VALENTIANA. _J. E. Gray._ Annals of Philosoph., vol. x (new series), 1825.
_L. scutis in profundam tergorum plicam invertis: tergorum opposito superiore margine, plica altera aeque profunda instructo: carinae crista prominente centrali, marginibus quadratis, in parte superiore: rostro rudimentali: lateribus et pedunculo ignotis._
Scuta locked into a deep fold in the terga; the latter having a second equally deep fold on the opposite upper margin. Carina with a prominent, central, square-edged ridge in the upper part: rostrum rudimentary.
Latera and peduncle unknown.
Animal unknown.
Red Sea, imbedded in an oyster-sh.e.l.l. British Museum.
_General Remarks._--The two specimens in the British Museum are small, and in an imperfect condition, without the peduncle or the latera, and without the body of the animal. The capitulum so closely resembles that of _L. truncata_, that it is quite superfluous to do more than point out the few differences. It is just possible, though not probable, that this form may prove to be merely a variety or younger state of _L.
truncata_, in which case this latter name would have to be sunk. The difference, though one only of degree, in the form of the terga of the two species is conspicuous, and there is a slight difference in the carina, and again some dissimilarity in habits.
_Description._--The valves, as just stated, generally resemble those of _L. truncata_; scarcely any appreciable difference can be detected in the scuta; the apex, however, of the inner surface seems coloured a darker purple. The terga, as seen from vertically above (Pl. VIII, fig.
5 _b_), have a fold or indentation on the upper or occludent margin, as large and as conspicuous as that receiving the margin of the scuta: this fold, as seen on the inner corium-covered surface (fig. 5 _a_), descends below the roughened k.n.o.b at the upper angle of the carinal margin, which is not the case with the slight fold in the same place in _L. truncata_; its presence seems caused by the edge of the central internal crest, in the upper part of the carina, being square (instead of round, as in _L.
truncata_), and thus more deeply affecting the outline of the terga, between which it is inserted. The upper part of the scutal margin of the terga, as seen internally (fig. 5 _a_), overlaps the scuta in a large _rectangular_ projection. From the depth of the two opposite folds, namely, that caused by the tergal edge of the scuta and that by the crest of the carina, the inner face of the tergum is divided into two almost equal areas. The carina has its central crest square (fig. 5 _c_, _d_,) instead of being rounded as in _L. truncata_. The inner growing or corium-covered face is nearly at right angles to the longitudinal axis of the whole valve, instead of being oblique to it; it is convex or protuberant, with a central raised line, and two little k.n.o.bs on each side of the upper part; the two lateral margins are slightly hollowed out, and the basal margin is not highly protuberant. The rostrum is excessively minute, barely above 1/200th of an inch in width; it is a little enlarged at each zone of growth. Latera lost; no doubt they were rudimentary.
A fragment of a posterior cirrus, which adhered to one of the valves, shows that each segment supported four pairs of spines.
Width of the capitulum before disarticulation, probably was about 1/10th of an inch.
_Species mihi non satis notae, aut dubiae._
ANATIFA VILLOSA. _Brugiere._ Encyclop. Meth. Des. Vers., tom. i, 1789, p. 62, Pl. clxvi.
On ships: Mediterranean.
ANATIFA HIRSUTA[69] _Conrad._ Journal of the Acad. of Nat. Sc., Philadelphia, vol. vii, 1837, p. 262.
On fuci, Fayal, Azores.
The specimens, to which these names have been given by the above two authors, are described as small, and the _A. villosa_ was suspected by Brugiere to be young. The _A. hirsuta_ is said by Conrad to have the valves minutely striated, granulated, and covered by a strong hirsute epidermis; the scuta, compared with the other valves, are very large; the entire length of this specimen was a quarter of an inch. The _A.
villosa_ is described as having smooth valves, and apparently the peduncle alone is hirsute. Now, in young individuals of _Lepas australis_, the peduncle is hairy, whilst in full-grown specimens it is quite smooth. Again, in some varieties of _L. fascicularis_, the thorax, prosoma, and cirri are hirsute, whereas they are generally quite smooth; hence I am inclined to suspect that _A. villosa_ is the young, in a state of variation, of _L. anatifera_; and that _A. hirsuta_ bears a similar relation to _L. anserifera_. In Lamarck"s "Animaux sans Vertebres," _Pollicipes villosus_ of Sowerby is quite incorrectly given as a synonym to the above _A. villosa_.
[69] The _Anatifa hirsuta_ of Quoy and Gaimard is the _Ibla quadrivalvis_ of this work.
ANATIFA ELONGATA. _Quoy_ et _Gaimard_. Voyage de l"Astrolabe, Pl.
xciii, fig. 6.
This, I think, is certainly a distinct and new species, but I am unable to decide whether to place it in Lepas or Paecilasma. It is briefly described and pretty well figured in the above work. It was procured at New Zealand, but it is not stated to what object it was attached. The capitulum is much elongated, and one inch in length; the peduncle is from six to eight lines long. The carina is said to be very narrow; it is not stated whether it terminates downwards in a fork or disc; judging from the figure, it extends some way up between the terga, the basal ends of which are bluntly pointed. The scuta are almost quadrilateral.