hand-slugs and Glass-shells 329 



that are covered with very thhi shells, in other 

 species the shell is reduced until it is only a small 

 plate acting as a protection to the breathing organs, 

 and then again it has been reduced to a few discon- 

 nected grains of shelly material that can serve no 

 defensive purpose. But, strange as it may appear, 

 this last section of the Land-slugs will not be dealt 

 with in this chapter but in the next, their affinities 

 being rather with the Common Garden Snail. 



With the slugs we begin our acquaintance with the 

 sub-order Stylommatophora, the Puhnonates that 

 have two pairs of tentacles which can be completely 

 withdrawn into the head, and that have their eyes 

 placed at the tips of the upper pair of tentacles. The 

 sexual organs (with a few exceptions) have a common 

 opening. The first family of these is the Testacellida\ 

 the Shelled Slugs, of which three species are found in 

 this country, but two are believed by some authorities 

 to be only doubtfully indigenous, and one has certainly 

 been introduced within the last century, though now 

 thoroughly naturalised in gardens throughout the 

 country. 



The Carnivorous Slug (Testacella haliotidea) is 

 about 3 inches in length, and at once strikes the 

 attention as being of a shape so strongly differing 

 from that of ordinary slugs. In these the broadest, 

 thickest part, containing the principal organs, is to- 

 wards the forepart of the body, which tapers away 

 behind to a slender tail. All this is reversed in 

 Testacella, whose stoutest part is to the rear, where 

 the shell covers the breathing organ. The animal 

 can elongate itself very considerably in order that 

 it may pass through the burrows of its special prey 



