GASTROPODS. 
343 
shaped, and are generally laid in the earth under stones or leaves, and there left 
to hatch by themselves. On emerging from the egg, the animals are practically the 
same as the parent, but the form of the shell, when present, generally alters very 
much in the course of growth. 
Shelled Slugs,— Family Testa cell id .r 
The shelled slugs, or Testacellidce, have no jaws, but are armed with a tongue 
bearing oblique series of long, narrow, pointed teeth, indicative of their carnivorous 
habits. While some members of the family are without any external shell, the 
majority are provided with shells capable of entirely covering the animals, but a 
few have only very small ear-shaped shells attached to the upper surface of the 
hinder end of the foot. To the latter group belongs Testacella, the typical form 
of the family. This genus includes elongated slug-like animals, with the breathing 
orifice at the posterior end of the body, which is capable of great extension and 
contraction. They prey upon earthworms, which are pursued in their burrows under 
ground. In a recent account of the habits of T. scutulum, Mr. Webb observes that 
it usually seized the anterior 
end of the worm, and gradu¬ 
ally swallowed it; but occa¬ 
sionally the middle was 
seized, in which case the 
worm forced itself away. 
During cold northerly and 
easterly winds these crea¬ 
tures enclose their bodies in 
a kind of cocoon, like that 
of the silk-worms, which is 
secreted from the skin, and 
often mixed with earthy and 
extraneous particles. These slugs deposit a few calcareous eggs, which in form 
are as symmetrical as those of a bird, and large in proportion to the size of the 
animal. It is doubtful whether this genus is truly indigenous to Great Britain, 
or merely an introduction of comparatively modern times. The only other parts 
of the world besides Europe where Testacella occurs, are Algeria and the Azores, 
Madeira, and Canary Islands. 
Glandina forms an extensive genus of Testacellidce, chiefly restricted to' the 
central parts of America; one species, however, being European. Like Testacella, 
these are very voracious, and even attack their own species. Daudebardia is another 
slug-like genus of this family, carrying a small shell upon the tail. They occur 
in Southern and Eastern Europe and Western Asia, and in New Zealand are closely 
represented by Schizoglossa, the external aspect of which is very similar. The 
allied Streptaxis is remarkable for the peculiar obliquity of the last or body-whorl 
in relation to the spire in most of the species. The first-formed part of the shell 
is regular in its growth, like an ordinary garden snail-shell, but suddenly the 
growth becomes irregular, giving the shells a very oblique and distorted appearance. 
The object of this deviation from the ordinary form of growth is not apparent, but 
shell-bearing slug, Testacella haliotidea (nat. size). 
