TESTAOEA. 23 



The under surface of a large fine yellow specimen is represented in 

 Plate v., Fig. 1. 



Most of the specimens which I have seen are grey. A small one is 

 shewn, fig. 2, upper surface ; fig. 3, under surface ; fig. 4, tentaculum and 

 eye, enlarged. 



Grey specimens attain nearly the dimensions of the yellow ones. 

 I have been unable to discover any important distinctions between 

 them. If the sjrphon of some has appeared long, the body triangular, 

 and the cloak expanding irregularly, it might be owing to the emaciated 

 state of the individuals, or other causes. However, the cloak, owing to 

 its colour, is more transparent than that of yellow specimens. A thin 

 slough is cast off the upper surface. — Fig. 5, upper surface ; fig. 6, under 

 surface. 



Under the cloak is a pure, thin, beautiful shell, of a very peculiar 

 form. In real structure it seems to approach three rotates, the first per- 

 forated, the last very wide and flattened. A grey specimen having died, 

 I committed it to a vessel of sea-water with a prawn, in hopes that the 

 animal would be consumed, and the shell left entire. This plan succeeded. 

 The same was done with another of an orange colour, which is not repre- 

 sented here. 



In the Sigaretus it is the cloak which, by its projection, forms a 

 snout.''' In the Tritonium imdatum, the Cyprsea, and others, it is the flesh 

 of the animal folded. 



The creature is partly pelagic, partly httoral. It is not common. 



Plate V. 



Fig. 5. Shell, back. 



6. The same, face. 



7. Shell of fig. 6, back. 



8. The same, orifice. 



* The reader will profit by consulting Cuvier, Sur les MoUusques, for the anatomy of 

 the Sigaretus; also Montagu, in Liiincean Transactions, vol. xi. p. 186; and the observa- 

 tions of Dr George Johnston, in London Magazine of Natural History, vol. ix. p. 229. 



