GASTEROPODES. 313 



rounded nearly as a circular arc, or extremely obtuse, including other 

 characteristics. But there are some wherein this feature is entirely 

 obliterated, the shoulders being prolonged into a triangular process, which 

 advancing progressively through several species, at length narrowly re- 

 sembles real tentacula ; and they seem to participate somewhat of their 

 nature. 



From its conformation, perhaps, this species may be approximated 

 to the Eolis viridis. 



Length, from the tip of the tentacula to the extremity of the tail, 

 fifteen lines ; breadth a line and a half. Body slender, tapering down- 

 wards to a point. Shoulder elongating in a slender recurving process, 

 very flexible. Head small and round ; mouth conspicuous below ; 

 cornicula somewhat taper ; deeply indented, tending to whorls ; a 

 black speck behind the root of each. Back bare, each side bordered by 

 five, six, or seven branchial tufts, according to the size of the specimen. 

 The papillae elongated, flattened, pointed, more prominent as the tuft is 

 higher. In an early stage they are merely stumps. Colour of the body 

 fine delicate purple ; all the extremities white. Centre of the papillse 

 red, amidst a lighter hue. In some specimens the white tip seems sur- 

 mounted by a black one. But the colour is not invariably purple, being 

 sometimes rather of various red, or tending to faint orange. Yet it is 

 always a beautiful and delicate looking creature, bristling up the papillae 

 when exposed to any annoyance. 



When quitting the side of the vessel to swim supine, the anterior 

 part of the body is folded together longitudinally. 



Fine specimens are not common. 







PLATE XLV. 



Fig. 19. Eolis purpurea. Back. 



20. Belly. 



21 . Another specimen : Back. 



22. The same : Belly. 



2 R 



