CALIFORNIA STALK-EYED CRUSTACEA. 217 



carpus of the second pair; carpus slightly longer than the merus; hand 

 very narrow, shorter than the carpus; fingers straight, subequal to the 

 palm. Second pair of pereopods slender and greatly elongated, the carpus 

 reaching beyond the rostrum; ischium, merus and carpus of subequal 

 length, the latter furnished with two teeth at the distal end; hand long, 

 very narrow, subcj'-lindrical, exceeding the length of the carpus and merus 

 combined; fingers slender, straight, about two-thirds as long as the palm, 

 the tips hooked and crossed when the fingers are closed. The ambulatory 

 legs are very slender, nearly naked, and subequal. The posterolateral 

 angle of the fifth abdominal segment is rounded, that of the sixth acute. 

 Telson with two pairs of dorsal spinules. 



Length of body, 18 mm.; of second chelipeds, 16 mm.; of hand, 7 mm.; 

 of carpus, 3 mm. 



Santa Catalina Island, August, 1893; three specimens. 



Closely allied to A. ensifrons Dana from north of 

 Borneo, but is distinct. Collection University of 

 California. 



Suhtribe PEN^IDEA. 



Gills dendrobranchiate. Third pair of pereopods and frequently the 

 first and second pairs chelate; the first pair never very large and stout, 

 usually smaller than the others. Fourth and fifth pairs of pereopods always 

 devoid of chelae. 



Family PEN^ID^. 



Carapace generally compressed and produced backwards at the sides. 

 Kostrum compressed and usually continued back upon the carapace as a 

 carina. Eye-stalks generally two-jointed. Antennules biflagellate; first 

 basal joint with an external spine and an unjointed appendage on the 

 inner side; upper surface excavated. Antennte long, with a large acicle. 

 Mandibular palp never more than two-jointed. Third maxillipeds long 

 and pediform. First three pairs of pereopods chelate and similar. Abdo- 

 men long and compressed, more or less carinated above; the sides of the 

 first segment produced so as to overlap the sides of the carapace in front 

 and those of the second segment behind. 



Genus Penaeus Fahr. 



Body strongly compressed. Kostrum prominent, serrated. Eye-stalks 

 two- or three-jointed. Flagella of the antennules not longer than the 

 carapace. Mandibular palp two- jointed. First three pairs of pereopods 



