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 Kolis 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 papilla 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 papille 
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 papille 
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. 
Piate XLV. 
Fig. 19. Holis purpurea. Back. 
20. Belly. 
21. Another specimen: Back. 
22. The same : Belly. 
