and gome new Species of Nudibranchiute Mollusca. 163 



shaped tongue (fig. 5) thickly covered with transverse rows of 

 hooked spines (fig. 6), with the points turned backwards. The 

 stomach is situated rather backward and low in the body. The 

 gastro-vascular system (fig. 7) passes out of it in several direc- 

 tions, dividing and branching into the papillae. The vessels which 

 pass into the branchial papillae are in the form of blind sacs 

 (fig. 8 a, and fig. 9), having no ovate vesicle communicating ex- 

 ternally through the end of the ])apilla as in Eolis. A large vessel 

 (fig. 8 b), howevei*, is observable enveloping the former and ex- 

 tending the whole length of the papilla, through which the blood 

 probably circulates. In other respects the internal anatomy of 

 this little animal, as far as we coidd make it out from the exami- 

 nation of a single specimen, appears to agree with that of Eolis, 

 excepting in the position of the alimentary canal and the poste- 

 rior dorsal anus. The heart is placed much further back than in 

 Eolis, and nearer the position which it occupies in the Dorid<e. 

 When examined under the compressor of a microscope the audi- 

 tory capsules (fig. 10) were observed in the usual position, con- 

 taining nearly thirty otolites. 



The species for which it has become necessary to form this 

 new genus we have called 



V. mucronifera. — Yellowish brown on the back, marbled and 

 spotted with darker brown. Dorsal tentacida tuberculated. 

 Branchia ovate, crystalline, covered with tubercular points; 

 set in twelve transverse rows of three papillse each on the sides 

 of the back, with four large papillae in front. 



It is nearly half an inch long. The back and dorsal tentacula 

 are of a pale yellowish brown colour, clouded and freckled with 

 darker brown, and sprinkled with minute white spots. The rest of 

 the body is of a hyaline white, nearly colourless, having a few small 

 brown spots on the head and on the margin of the foot, mbced 

 with more numerous opake white ones. The back is depressed 

 and slightly roughish ; the sides smooth and rather concave. The 

 veil is small and strongly notched in front ; from its sides arise 

 two small cylindi'ical oral tentacula. The dorsal tentacula are 

 linear, subconical, and covered with tubercular points. The 

 branchiae are ovate or inversely pear-shaped, produced into blunt 

 points at the apex, and having rather distant tubercular points 

 over the whole surface, giving the more slender of them a pin- 

 nacled appearance. They are very crystalline and almost colour- 

 less, having only a small yellow tube with undulated margins in 

 the centre, and are sprinkled with numerous opake white spots 

 over the surface. They are set along the projecting sides of the 

 back in about twelve ill-defined transverse rows of three papillae 

 each, very close at the base ; those next the back being large and 

 inflated, the exterior ones very small : two larger than the rest are 



M 2 



