WEBB : BRITISH SPECIES OF TESTACELLA. 5I 



names is a matter for rejoicing, but it is advisable, nevertheless, 

 that all important variations should be recorded. 



Testacella scutulum. 



It is unlikely that many forms of T. scutiiliiin would be re- 

 corded, for until recently, it was itself considered to be a variety. 

 The writer recalls, however, some " sub-varieties " he thinks, 

 from Gibraltar, described in " Science Gossip " a number of 

 years ago by Mr. Cockerell, who has raised them to varietal 

 rank in his " Check List of Slugs." * 



The first two of the variations noted below as occurring in 

 the British Isles, appear to correspond with a like number of 

 Mr. Cockerell's "varieties." 



Yellow form. — With dots. 

 Bright yellow form. — Without dots. 



Brownish form. — The dots are very close, or have run together, thus 

 giving the form a colour likeness to T. haliotidea. 



In addition, it may be said that the dorsal furrows are (even 

 when the dots are present) sometimes pigmented, sometimes 

 not, and that when the general appearance lightens, the foot-sole 

 whitens. In some specimens there is an orange margin to the 

 foot -sole. 



Testacella haliotidea. 



If the "Check List" be again referred to, some seven 

 " varieties " are given of T. haliotidea : these may or may not be 

 based upon correctly determined specimens of the species. 

 Several of the names have reference to slight variations in the 

 shell alone, which could easily be picked out from a good series, 

 such as the one before the writer. The albino is worth noting, 

 and there is a yellow form also named by Moquin-Tandon which 

 is really represented in T. haliotidea. 



Among British examples, the writer identifies the fol- 

 lowing : — 



Isabelline form. The body is compressed dorsiventrally, and its edges 

 are wavy, giving a foliaceous appearance, which is enhanced by the mid- 

 rib-like dorsal furrows with the lateral grooves running forwards and out- 

 wards from them, while other grooves often run in like manner up into the 

 spaces between dorsal furrows. The foot-sole is quite white, but the sides are 

 often tawny, this colour sometimes spreading to the back. This is by far the 

 most general form. 



* Journal of Malacology, vol. ii. (1893), p. 188. 



