INDIAN NUDIBRANCHIATE MOLLUSCA. 133 



The anatomy of Plocamophorus corresponds very nearly with that of Polycera. The 

 buccal organ is large. The tongue (in P. ceylonicus) has eighteen rows of plates, 

 twenty-four to twenty-six in each row ; the central space is bare, without any plate ; 

 the three plates on each side next the centre bear two large broad spines ; beyond these 

 on either hand there are nine or ten elongated and squared plates with elevated centres. 

 The buccal lip is supplied with an incomplete collar, open above and wide below ; it is 

 stiff and almost horny, and has the surface covered with rather long, stout, bristle-like 

 processes. 



The oesophagus as it leaves the posterior extremity of the buccal organ is much con- 

 tracted, and has on either side, opening into the mouth, a long tubular salivary gland. 

 The alimentary tube almost immediately expands into an elongated anterior stomach 

 or crop. This becomes constricted again as it approaches the anterior extremity of 

 the liver; and penetrating that organ, it is enlarged once more, and assumes the cha- 

 racter of a second stomach of rather limited dimensions. The intestine is a moderately 

 long tube ; it passes from the anterior wall of this stomach, and issuing through a cleft 

 on the left side of the liver, turns backwards to terminate in an anal nipple within the 

 branchial circle. The liver is an ovate mass, rounded behind and truncated in front ; 

 it throws the hepatic fluid into the second stomach by two ducts which open in the 

 floor of the organ, one on each side of the pyloric orifice. 



The reproductive organs resemble, in their general features, those of Polycera qua- 

 drilineafa ; but in the place of the large laminated organ in connexion with the glandular 

 tube leading to the penis, there is a beautiful dendritic gland, composed of several 

 distinct systems of ramuscules, which are spread over the large spermatheca, forming 

 for it a sort of open capsule, as the mace does for the nutmeg. The ramuscules are 

 connected by their trunks to the inner extremity of the tube attached to the penis ; and 

 at the point of junction the usual connexion of the oviduct with the male apparatus is 

 effected by a short, slender duct. The vascular system does not appear to differ from 

 that of Polycera ; and the nervous centres closely resemble those of P. quadrilmeata, 

 all the principal ganglions being distinct and lying above the oesophagus. 



Plocamophorus ceylonicus, Kelaart, sp. (PI. XXXII. figs. 4, 5, 6.) 

 Body oblong, tapering behind, of a yellowish fawn-colour, spotted and blotched with 

 warm brown: the blotches largest on the back, where they assume some degree of 

 symmetry, there being usually a large, elongated, branched blotch between the ten- 

 tacles, and another between the first pair of pallial processes, with smaller ones behind. 

 The surface is covered with delicate, pale, branched papillae. Mantle obsolete on the 

 sides of the body, where its position is indicated by three pairs of branched processes, 

 the two posterior pairs having their extremities enlarged and rounded : in front the 

 mantle is produced into an ample arched veil, the margin bearing a fringe of numerous 

 branched processes of various sizes : the veil is marked and coloured like the body. 



