THE VICTORIAN NATURALIST. 95 



would mention a few peculiar crustaceans, of which large 

 numbers are found in tropical seas and among the gulf weed. 

 They are all vitreous, and not thicker than a sheet of paper. 

 As examples, I may mention " Erychtheus vitreus," " Alima 

 hyalina," and " Phyelosoma commune" or the crystal crab. 



We now come to those mollusks which have a regular shell 

 covering, and we will first notice the " Janthina," or common 

 blue sea snail. These are most frequently taken of all the 

 surface shells, and are found floating plentifully in all the warm 

 latitudes at all hours of the day or night. It is supposed that, 

 like all the snail tribe, they subsist upon some weed which floats 

 in the ocean. One remarkable feature in these pretty shells, 

 which vary in size from that of a pea to that of an ordinary 

 garden snail, and in colour from a pale blue or lavender to a 

 rich purple, is the provision they make for the protection of 

 their eggs or young, which are attached to the under surface of 

 a sort of float or raft which the parent keeps attached to it 

 wherever it goes. Then I frequently caught a fine large shell 

 known as " Hyalea tridentata," of which there are several 

 species. These have a large projection like an immense under 

 lip, and the base of the shell terminates in three sharp points. 

 Akin to these are the " Diacria," of which there are also 

 several varieties. They have no projecting lip, but only an 

 oval-shaped orifice, which in some species is fringed with a 

 handsome bright red edge. 



"Cleodora lanceolata" is a beautiful crystalline shell with a 

 very large orifice, and is most beautifully marked externally with 

 a number of transverse bands. 



The "Atlanta Peronii," a species of paper nautilus, is 

 another species very numerous in some parts of the ocean, 

 many thousands being frequently taken in one haul. Like the 

 preceding shell, they are very vitreous and delicate to handle 

 and clean the fish from. 



" Cuvieria columnella," to which I gave the name of the 

 Hyacinth glass, is a pretty shell of a cylindrical shape, per- 

 fectly transparent, with a simple aperture. It has two small 

 fins, which are united ventrally by two small lobes. 



•' Creseis aciculata," which is a sub-genus of Cleodora, has a 

 slender vitreous shell, conical, and running to a sharp point 

 with narrow fins, which have small tentacles projecting from 

 the dorsal edge, most difficult to preserve without injury. 



The last shell which I shall mention, whose scientific name I 

 have not been able to discover, and certainly the least of all my 

 specimens, was captured in large numbers one evening when 

 we were almost becalmed off Cape Horn, from which I have 

 called it the " Cape Horn Shell." When showing some of my 

 specimens many years ago to that great and clever naturalist, 

 Professor (now Sir Richard) Owen, he was much surprised to 



