-26 G. 0. Sårs. 



height than in the usual form, though otherwise it exhibits 

 ■a very similar shape. The hnes of growth are about 18 in 

 number on each valve, and are rather regularly arranged, 

 the outer ones being scarcely more densely crowded together 

 than the others. As to the structure of the enclosed animal, 

 the head with its appendages and the tail do not seem to 

 exhibit any appreciable difference from those parts in the 

 other specimens examined. On the other hand, the prehensile 

 legs (see figs 5 and 6) appear pronouncedly shorter and more 

 robust than usual, with the hand comparatively short and 

 broad, and having the obtuse prominence above the thumb 

 very strongly marked. In spite of the above-mentioned 

 differences, I do not feel justified in establishing a new 

 species for this solitary specimen, considering the consider- 

 able variations which in reahty exist in other specimens 

 unquestionably belonging to one and the same species. 



