60 EAMBLES IN SEAKCH OF SHELLS. 



convex, the suture not so oblique, and the mouth 

 broader in proportion ; it has also a varnished appear- 

 ance, which is wanting in the smaller kind. I kept 

 many of both kinds alive for a considerable time, and 

 watched their habits. Several paired in captivity 

 and deposited eggs, but though kept together they 

 never united, except with their own sort. The large 

 kind I observed rather to avoid the water, whereas 

 the small often took to it of their own accord, and 

 remained in for a length of time, particularly at 

 night. I have this year lost dozens of the smaller 

 Succinea through the ravages of a small worm, pro- 

 bably a Cochleoctonus. More than once, while look- 

 ing at my captives, I have noticed an individual 

 become restless and begin to throw its head from 

 side to side. Shortly after a worm has made its 

 appearance, usually by eating its way through the 

 right side of the neck of the Succinea, just above and 

 behind the genital orifice. The poor victim seldom 

 lived more than an hour or two after the exodus, and 

 seemed to die in great pain, as the genital organs 

 and ' poche buccale ' often protruded, as if they had 

 been squeezed out by strong convulsions." The 

 writer adds, by way of postscript (p. 8171) : 



