içog.] N. AnnandaIvK : The Indian Cinipedia Peduncidata. 79 



shaped joint, which bears on its posterior margin a series of very minute chitinous 

 points ; on the narrow, distal part of the appendage these become longer and are 

 arranged in annular series ; they are absent from the basal part of the anterior margin. 

 Penis long and slender, rounded at the tip, indistinctly annulated in the middle, bear- 

 ing numerous fine, scattered hairs. One filamentous appendage on each side. 



Mouth parts. — Lahrum feebly or not at all bullate. Outer- maxilla broad and 

 short. The palp conical, with a dense fringe of rather short bristles on its outer 

 margin. Maxilla with the free edge very broad, armed at the outer extremity with 

 a single stout spine and two more slender spines of unequal length, which are followed 

 by a deep, wide excavation ; following this are two shallow excavations separated by 

 rather wide prominences, the whole edge being armed with numerous bristles. 

 Mandible with six teeth including the internal angle ; the five innermost subequal, the 

 external tooth being larger than, and rather widely separated from, the others ; the 

 whole of the sixth tooth, the outer margin of the fifth, fourth, third and second, and 

 the excavation between the second and the external tooth, bearing very short spines. 



The only known specimens of this species were taken on a sea-snake {Hydrus 

 platurus) off the coast of Ceylon ; some of them are now in the Colombo Museum, the 

 remainder in Calcutta. 



Genus Conchoderma, Olfers (18 14). 



Darwin defines this genus as follows : — 



"Valves 2 to 5, minute, remote from each other; scuta with two or three lobes, 



with their umbones in the middle of the occludent margin ; carina arched, 



upper and lower ends nearly alike. 

 '* Filaments seated beneath the basal articulations of the first pair of cirri, and 



on the pedicels of four or five anterior pairs ; mandibles with five teeth, finely 



pectinated ; maxillae step-formed; caudal appendages, none." 



The relations between Conchoderma and Lepas are comparable to those between 

 Dichelaspis and Pœcilasma , but are much less close. Nothing that can be called an 

 intermediate form is known, for the degeneration in the valves of Lepas tenuivalvata 

 is of a wholly different kind from that which has taken place in Conchoderma, nor does 

 the former lack caudal appendages or possess a large number of lateral filaments. 

 Indeed, it would rather appear that the two genera were offshoots from a common 

 stock than that one was an offshoot from the other. 



The only known forms, according to the view adopted here, that can be distin- 

 guished as species are C. virgatum (Spengler) and C. auritum (Linn.). Both of these 

 species are said by Darwin to be '' mundane," but I can find no definite record of the 

 occurrence of C . auritum in the Indian Ocean, although it is apparently common in 

 all parts of the Atlantic and Pacific. 



Both species are commonly found attached to floating objects or pelagic animals, 

 but C. virgatum also occurs at the bottom, both on inanimate objects and on Crus- 

 tacea. 



