86 
HELICID^. 
subglobular shelly which is partly covered by 
the back edge of the shield, and a tongue -like 
process of the mantle on the 
right side. J aw strong, lunate, 
smooth, with a strong central 
projection ; tongue broad ; teeth 
numerous, with a single pro- 
longed apex to the edge tooth, like Limax. 
Shell imperforated; spire depressed, of only a 
few whorls ; mouth large, rounded, lunate ; 
peristome thin. 
This genus is intermediate in form between a 
slug and a snail, having the shield-like mantle of the 
one, and the globular external shell of the other 
genus. The shells are very like the Zonites in their 
appearance, but have a much smaller and more de- 
pressed spire, more rapidly enlarging whorls, and 
a much larger mouth ; but they are best known by 
their axis being imperforated. 
Nilson kept some specimens, which he had caught 
at the end of January, in a bell glass ; and on the 
19th of February he observed some eggs placed 
among the putrescent leaves. The eggs were oval, 
globose, white, subpellucid, with a central opaque 
spot, and placed in little tufts, consisting of eight or 
nine eggs. In the beginning of March the opaque 
spot was not increased in size, but showed signs of 
slow movement; and on the 21st or 22nd of March 
the animals were excluded. He thought, when he 
observed them with the microscope, that the animal 
bored its way through the egg-shell, forming a hole 
out of which first the head, and then the foot, was 
