168 S. I. Smith on American Crustacea. 



slight depression only. The front projects slightly and is not so much 

 deflexed as in the female. 



The chelipeds and ambulatory legs are like those of the female, 

 except that the ambulatory legs of the right side are like those of the 

 left. 



The abdomen is broadest at the third segment, fi'om the third to 

 the sixth, the margins are straight and converging, the sixth is 

 abruptly contracted, and the terminal segment is nearly square. The 

 appendages of the first segment are rather stout organs, somewhat 

 hairy along the margins, and reach to the terminal segment. They 

 curve inward for about two-thirds of their length and then outward 

 again to the tips. Tlie appendages of the second segment are short 

 and are lodged in grooves at the bases of the first pair of appendages. 



Locality. Sex. Length of carapax. Breadth of carapax. Ratio. 



Pearl Islands. Male. 5 Smni Q-imxa i ; in 



La Paz. Female. 8-1 8-9 1:M0 



Pearl Islands. ' 8-8 9-7 1:1-10 



•' " 100 11-0 1:110 



" " 10-3 11-4 1:111 



" " 10-9 12 1:110 



" " 11-8 13-4 1 : M4 



This species was found living in the Pearl Oyster (Margarito- 

 phora fimhriata Dunker), at the Pearl Islands, Bay of Panama, by F. 

 H. Bradley, It has also been sent from La Paz, Lower California, by 

 Capt. J. Pedersen. 



A sterile female Pinnotheres, found in an alcoholic specimen of the 

 Pearl Oyster collected at the Pearl Islands by Mr. Bradley, probably 

 belongs to this species. It agrees closely with specimens of P. m.ar- 

 garita, described above, in the form of the external maxilli]»eds and 

 the firm integument. 



The carapax is more like the male than the ordinary female, but is 

 narrower and more depressed. The front is more prominent and 

 scarcely at all deflexed. The dorsal surface is very slightly areola- 

 ted, quite flat, and is clothed, except the cardiac region and a small 

 space in the middle of the gastric, with a very dark, almost black, 

 velvety pubescence. 



A single cheliped is stouter in proportion than in the ordinary male 

 and female, and the pubescence upon the upper surface of the carpus 

 and a small space at the base of the hand, is black as on the dorsal 

 surface of the carapax. 



The ambulatory legs are less pubescent than in the male, while the 

 propodus and dactylus of the right leg of the second pair are longer 



