INDIAN NUDIBRANCHIATE MOLLUSCA. 139 



hyaline variety is represented among Mr. Elliot's drawings, which seems to be Kelaart's 

 species, but is assuredly the young oi M. fimbriata. 



This species is tolerably frequent, but is difScult to preserve entire on account of the 

 deciduous nature of the processes. It has a delicate and gelatinous appearance when 

 alive. 



Two or three mutilated specimens are in the collection. 



M. fimbriata differs from the M. rosea of Rang in the form of the branchiee, which in 

 the latter are claviform, with rounded tops, and beset with stout tubercles. The body 

 of M. rosea likewise appears to be smooth. 



Family DENDRONOTID^E, Alder 8f HancocA. 



Genus Bornella, Gray. 



Body compressed, without cloak. Tentacles two, retractile within branched sheaths. 

 Head with two branched or fimbriated appendages. Branchise plumose and papillose, 

 arranged on foot-stalks, in single series on each side of the back. Anus lateral. Tongue 

 narrow, with a large, broad, denticulated, central spine, and several smooth lateral spines 

 on each side. 



The anatomy of this genus confirms the opinion (that might be inferred from its 

 external characters alone) of its close relation with Dendronotus. The organic structure 

 in the two forms agrees throughout in almost every particular. 



The buccal organ is rather large, and is armed with corneous jaws and a spiny pre- 

 hensile tongue, which is supported on the ridge of a wedge-shaped muscle that rises 

 from the floor of the mouth. The armed membrane is supplied with from thirty-eight to 

 forty transverse rows of spines, a large broad central spine with the margins denticu- 

 lated, and on each side of it nine smooth comparatively slender ones. Two dendritic 

 or folliculated salivary glands pour their secretion through delicate ducts into the 

 posterior extremity of the buccal organ, one on each side of the oesophagus. 



The oesophagus is rather long and slender : it opens into the anterior extremity of 

 the stomach, which is well defined, rather large, and of an oval form. The latter has in 

 the interior a broad transverse belt of soft, recurved, pointed papillae, arranged in close- 

 set longitudinal rows. The hepatic duct enters just in front of this belt ; and a large 

 fold of the mucous membrane, which passes from the intestine, advances to its posterior 

 margin. It is difficult to say what is the function of this peculiar papillose structure, 

 though, from its position, it may possibly be a modification of the supposed pancreatic 

 organ in Melibe. 



The intestine is extremely short : it issues from the posterior extremity of the stomach, 

 and goes to the right side of the animal, where it terminates in an anal nipple between 

 the first and second branchial tufts. 



