170 S. J. Smith on American Crustacea. 



pi. 11, fig. 11), but the merus is wider at the distal end and the outer 

 margin is not so arcuate. 



The chelipeds are equal and all the segments are rounded, smooth, 

 and glabrous. The hands are small and much compressed. The fin- 

 gers are shorter than the basal portion of the propodus, do not gape, 

 and the dactylus is slightly curved and is armed, near the base, with 

 a small tooth, which fits a slight excavation in the propodal finger. 



The ambulatory legs are short, slender, cylindrical, and smooth. 

 Those of the first pair are shorter than those of the second, and the 

 dactyli, in both the first and second pairs, are very short and curved, 

 and close against the expanded end of the propodus, which is clothed 

 at that point with a little tuft of short, stiff hair. Those of the third 

 pair are about the length of those of the second pair, and the dactyli are 

 short and curved, but the distal ends of the pi-opodi are not expanded 

 for their reception. The posterior legs ai*e sliorter than those of the 

 second or third pair, are much more slender than any of the others, 

 and the dactyli are only slightly curved and are very long and slen- 

 der, their length being about equal to that of the propodi. 



The abdomen is very broad and covers the whole sternum. 



Length of carapax, 5*4™™; breadth of carapax, 7'3™"i; ratio, 1 : 1'35 



a a a g.3 a a a g.3 a 1.1-32 



" » " 6-4 " •' •• 8-5 " 1 : 1-33 



Collected at Callao, Peru, by F. H. Bradley. 



The integument is quite thin and yielding, and the species undoubt- 

 edly lives protected within some bivalve mollusk (probably Mytilus 

 algosus Gould). It appears to difier remarkably from the other species 

 of the genus in the depressed carapax and naked ambulatory legs, 

 and I refer it to Edwards' genus with some doubt, although it agrees 

 in the two-jointed palpus of the external maxillipeds. 



The other described species of Ostracotheres are : — 0. Savignyi 

 Edwards {Pinnotheres veterum Savigny), from the Red Sea ; O. Tri- 

 dacnm Edwards (Ruppell), also from the Red Sea; and 0. affinis 

 Edwards, from the Isle of France. 



Pinnaxodes Heller. 

 Pinnaxodes Chilensis Smith. 



Pinnotheres CMe?ms Edwards, Histoire naturelle des Crust., tome ii, p. 33, 1837; 



Edwards et Lucas. Voyage de d'Orbigny dans I'Amerique meridionale. Crust., p. 



23, pi. 10, fig. 2, 1843. 

 Fahia Chilensis Dana, United States Exploring Expedition, Crust., p. 383, 1852. 

 Pinnaxodes hirtipes Heller, Reise der osterreichischen Fregatte Novara um die Erde, 



p. 68, pi. 6, fig. 2, 1865. 

 Pinnaxodes Chilensis Smith, in Verrill, American Naturali'tt, vol. iii, p. 245, 1869. 



