500 



Mr. R. Guiney on some Brltisli and 



the smaller, and that the posterior sulcus Is margined by a 

 few small spinules. 



The telson of A. simplex, Ghigi, differs from the type only 

 in a slightly different arrangement of the posterior marginal 

 spinules, while A. apulius, Ghigi, is distinguished by having 

 two strong median dorsal spines in front of the usual 



Fig. 2. 



}0^i=^ 



Dorsal view of telson. Specimens from: A and B; Scotland ; 

 0, Tunis; D; Algeria (Laghouat). 



posterior median spine, and also a few spinules on the 

 dorsal surface laterally. 



Now, although the Algerian and Tunisian specimens show 

 very little variability with regard to the telson, they do vary 

 to some extent : — 



[a) Six out of ten have exceedingly small denticles 



