44 



lung, or breathing chamber. From the posterior margin of the 

 shield there sometimes runs a keel along the back down to the tail. 

 In front of the shield lies the head. This is mostly all we see when 

 the slug is at rest. When active it thrusts out the tentacles, the 

 upper pair bearing eyes on their summits and olfactory nerves, the 

 lower pair being smaller and destitute of eyes. At the edge of the 

 mantle on the right side of the animal we see the large aperture of 

 the breathing chamber, this luay be opened or closed at the will of 

 the animal. There is no aperture on the left side except in sinistral 

 specimens, which appear to be extremely rare. The shell slugs, of 

 which we have three species, may be recognised from all the 

 others by the small shell which thej^ carry near the end of their 

 tails. The heart and the opening of the breathing chamber are 

 also situated in this part of the animal. They are strictly car- 

 nivorous, feeding chiefly on earth worms, and, like their prey, they 

 pass a great deal of their life under the surface of the earth. 

 Though stout when at rest, the shell slugs can elongate their bodies 

 in a surprising manner, so that they can follow the worms into 

 their burrows, and if they carried the mantle on their backs like the 

 other slugs it would get in the way. 



You will no doubt remember a splendid exhibition of Testacella 

 haliotidea made by Mr. West, of Ashtead, in this room some time 

 ago. This species was the first known of the shell slugs, it having 

 been discovered near Dieppe, in 1740. It appears to be fairly well 

 distributed over England. It may be known by its whitish-cream 

 colour and particularly by the lateral grooves being distinctly, but 

 not widely, separated at their origin in front of the shell. These 

 two grooves run from the shell along the body of the animal. 

 When hungry they will seize the end of a worm protruding from its 

 hole, and when the worm thus roughly treated retires, it is said, that 

 the slug elongating its body allows itself to be drawn down the hole 

 with its victim, thus obtaining food and cover at one fell stroke. 

 Those I had did not always wait to get the end of the worm, but 

 would seize it in the middle and slowly engorge it while the tw© 

 ends were moving about. It was certainly a gruesome spectacle to 

 behold. 



In 1823 G. B. Sowerby discovered Testacella scKtuliim in a garden 

 in Lambeth, but for many years it was generally considered only a 

 variety of the last species, as its anatomical difterences were then 

 not known. From the last species it may be separated by its 

 tawny colour and in the grooves which join together in front of the 

 shell. I have sometimes found this species on the garden path or 

 at the foot of a wall, but more often under lo^^s or by chance when 

 digging. It IS usually covered by an earthy coat, and its ochreous 

 colour is not well seen till this is removed. It was this species that 

 Tapping described as T. niedii-teinpli, having found it in the Middle 

 Temple Gardens. 



The third species, Testacella niait/jei is named after M. Mauge, 



