206 SMITHSONIAN MISCELLANEOUS COLLECTIONS 



320. PAGURUS STRIATUS ' Latreille 



Pagurus striattis LatrEillB, Hist, des Crust., vi, 163. Milne Edwards, 

 Hist. Nat. des Crust., 11, 218. 



If this be the Cancer arrosor of Herbst, which is quoted for it by 

 all European authors, we are at a loss to know why that name is not 

 adopted. 



Found in a Cassis sulcosa taken off the south side of Madeira, 

 near Funchal, in thirty fathoms. 



321. PAGURUS PLATYTHORAX = Stimpson 



Pagin-its platythorax Stimpson, Proc. Acad. Nat. Sci. Phila., x, p. 246 

 [84]. 1858. 



Body much depressed. Carapax above naked, smooth, and glossy. 

 Eyes large, reaching beyond the tips of the peduncles of the antennae 

 and antennulse. Ophthalmic scales with a tooth on the inner margin 

 near the base ; apex bidentate. Acicle very small. External maxil- 

 lipeds slender, somewhat flattened, a little separated at their bases, 

 which are exposed, their attachment to the triangular offset forming 

 the apex of the sternum being distinctly visible, not contracted in- 

 ward and concealed as in other species ; exognath slender. Feet 

 coarsely hairy. Chelipeds small, equal ; carpus and hand not spin- 

 ulose, but roughened above and externally at the bases of the hairs. 

 Ambulatory feet depressed, not spinous. Genital aperture of the 

 male on the inner slope of the coxa, and not fringed. Sternum 

 broad, flat, triangular, and broadly exposed between the chelipeds ; 

 no suture between the segments corresponding to the chelipeds and 

 the first ambulatory feet. Terminal lobes of the caudal segment 

 equal. General length, 1.4; length of carapax, 0.32; breadth of 

 front, 0.28; length of chelipeds, 0.45 ; length of eye, 0.17 inch. 



This species is always found in a cone or strombus, its depressed 

 form being a special adaptation for the occupation of the narrow 

 cavities of such shells. The remarkable characters of the sternum, 

 etc., result directly from the form of the body, and the general 

 widening of its parts, and cannot be considered as of generic value, 

 particularly as all that set of characters upon which the genera are 

 based in the family are those of the true Pagurus. 



Pagurus platythorax is allied to P. fahimanus and P. scahrimanus, 



^ Dardanus arrosor (Herbst). 



' Dardanus platythorax (Stimpson). 



