1904.] FKOM EAST AFUKA AXD ZANZIBAR. 85 



consist of about 27 small tufts, pinnate, bipinnate, or tripinuute 

 according to theii- size, and spread over three areas corresponding 

 to the valves. Possibly each ai-ea 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 i-etracted into simple 

 holes, provided with neither vah^es 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 rudimentaiy denticle 

 under the tip of the hook. They much resemble the teeth of 

 JVotodoris cifrina (Bergh, I. c. pi. ix. figs. 39, 40), but are somewhat 

 more erect antl hardly ever show indications of more than one 

 denticle (fig. 1.^). The glans penis spreads out somewhat as in 

 Xemhrolha, and appears to be tiifid. The lower part is armed 

 with a thick mass of minute blunt spines (fig. 1/). 



TiiEVELYAXA Kelaai't. 



[Kelaart, in Ann. Mag. Nat. Hist. 3rd ser. vol. i. p. 257, 1858; 

 Bergh, in Semper's Reisen, Heft xi. p. 441, & xvi. 2, p. 850.] 



This genus is recorded only from the Indo- Pacific, where it 

 seems to be the commonest representative of the Polyceradte, 

 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 

 vaiying from red to white. Tlie branchiae are rarely less than 

 ten, often numerous, and generally small. There is no labial 

 armatui-e or central tooth. Tlie radula is fnirly wide, and com- 

 posed of hamate or awl-shaped teeth, which are often nn-egular. 

 The hermaphrodite gland, instead of being spread over the liver, 

 is collected into two globular masses. 



Several of the species, e. g. the T. cei/lonka and T. hicolor given 

 below, are very imperfectly descrilied by the original authointies, 

 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. 



Trevelyaxa coccixea, sp. n. (Plate III. tigs. 2 «-2/.) 

 One specimen, dredged between Shimoni and Wasin at 6-8 

 fathoms. 



The notes on tlie living animal describe it as the largest species 



[3J 



