OCR Text |
Show 1904.] FROM EAST AFRICA AND ZANZIBAR. 85 consist of about 27 small tufts, pinnate, bipinnate, or tripinnate according to their size, and spread over three areas corresponding to the valves. Possibly each area represents a separate axis, and the gills should be described as three tripinnate or quadripinnate plumes. But this arrangement cannot be demonstrated with certainty in the preserved specimen, and the living animal never raised the valves at all. The rhinophores are thick, conical, and without a trace of perfoliations; they are retracted into simple holes, provided with neither valves nor raised edges. No oral tentacles and no groove in the anterior margin of the foot could be discovered (fig. 1 e). There is no trace of armature on the labial cuticle. The radula consists of 33 rows, the largest of which contain about 25 teeth on each side of the rhachis. The teeth are transparent and crowded: the innermost are smaller and close over the rhachis; the outermost are longer and show no trace of irregularity. The shape of all is much the same, hamate with a rudimentary denticle under the tip of the hook. They much resemble the teeth of Notodoris citrina (Bergh, I. c. pi. ix. figs. 39, 40), but are somewhat more erect and hardly ever show indications of more than one denticle (fig. 1 g). The glans penis spreads out somewhat as in Nembrolha, and appears to be trifid. The lower part is armed with a thick mass of minute blunt spines (fig. 1/ ) . T r e v e l y a n a Kelaart. [Kelaart, in Ann. Mag. Nat. Hist. 3rd ser. vol. i. p. 257, 1858; Bergh, in Semper's Reisen, Heft xi. p. 441, tfe xvi. 2, p. 850.] This genus is recorded only from the Indo-Pacific, where it seems to be the commonest representative of the Polyceradae, being frequent under stones between tides. The animals are limaciform, but some specimens at any rate show indications of a division between the back and sides. The body is smooth, bears no appendages, and is usually of a light bright colour varying from red to white. The branchife are rarely less than ten, often numerous, and generally small. There^ is no labial armature or central tooth. The radula is fairly wide, and composed of hamate or awl-shaped teeth, which are often irregulai. The hermaphrodite gland, instead of being spread over the livei, is collected into two globular masses. Several of the species, e. g. the T. ceylonica and 7. bicolor given below, are very imperfectly described by the original authorities, and hence identification is uncertain. It is clear that the whitish forms with yellow lines and spots show considerable variety, but it is hard to say how many of these varieties are specific. T r e v e l y a n a c o cc in ea, sp. n. (Plate III. figs. 2 a-2/.) One specimen, dredged between Shimoni and Wasm at 6-8 fathoms. . . The notes on the living animal describe it as the largest species |