ELIOT NUDIBRANCHS 139 



Sandwich Islands (Pease in Proc. Zool. Soc. 1860, page 29), which will thus be a pale 

 variety of Chr. petechialis. 



Plocamopherus ceylonicus (Kelaart). 



Alder and Hancock, On a Collection of Indian Jfudibranchiate Mollusca, 18G4, pp. 132-4. For 

 PI. imperlalis, see Bergh in Verhandl, der k.k. zoolog. botanischen Gesellschaft in Wien, 1883, pp. 12-17, 

 and for PI. ocellatus, Eliot in Linn. Soc. Journ. Zool., vol. 31, November, 1908. 



Five specimens from Kiu. Their delicate and gelatinous consistency has caused 

 all of them to be much contracted and distorted in the preserved condition, and it 

 is difficult to give any satisfactory description of the external characters. The general 

 shape was probably as in Alder and Hancock's figures of Plocamopherus ceylonicus : 

 the oral veil very large, the branchial tuft large and central ; the dorsal ridge on 

 the tail only moderately developed, but distinct. 



As preserved the specimens vary from 15mm. to 35mm. in length. The 

 coloration also is variable and in many cases the epidermis has been rubbed off. 

 As a rule the ground is transparent and colourless or faint yellow, but is covered in 

 most parts by irregular mottlings of a beautiful brown of varying shade and intensity. 

 They are deepest in colour and most regular in arrangement on the back. Among 

 these mottlings are fairly numerous white or cream-coloured areas, distinct but 

 irregular in outline. They are either plain or contain numerous small dots. The 

 club-shaped tips of the dorsal processes are of a dull plum colour. 



The large oral veil bears numerous processes (as many as thirty in large 

 specimens), which are pinnate or sometimes bipinnate, but as preserved quite small, 

 rarely attaining a millimetre in length. In all the specimens the head parts are 

 much contracted and it is impossible to say anything about the tentacles or the 

 pedal groove. There are three fairly large processes on either side of the back, 

 much contracted, but evidently bearing several branches. They bear as a rule at the 

 end a single round knob, which in all the specimens is of a dull plum colour and 

 contrasts with the rest of the integuments. In three specimens all the processes 

 have this knob : in one it is absent in the right anterior process, and in another 

 both the anterior processes are ramified, but without a knob. This is the condition 

 described by Alder and Hancock as found in PI. ceylonicus. There are a few 

 other smaller processes scattered over the back and sides. They are more 

 numerous in one specimen than in the others. There are traces of processes on 

 the caudal ridge. The branchiae are large and strong, mottled like the back, 

 and five in number. The rhinophores are whitish and retractile into cavities with 

 papillate margins. 



The labial plates are yellow or brown and triangular. The radula varies in 

 colour from light yellow to dark brown. The rhachis is very broad and traversed 

 by cross-lines. There are from fifteen to eighteen rows of teeth. The anterior rows 



