ISOPODS OF NORTH AMEHlCA. 5 



1. Genus PANCOLUS Richardson. 



Eyes present, distinct. First pair of antennae composed of three 

 articles. Second pair of antenna? composed of five articles. First 

 thoracic seg^ment permanently united with the head to form a cara- 

 pace. The following- six segments are free and distinctly separated. 

 The abdomen is composed of only three segments, two segments 

 anterior to the terminal segment. There are but two pairs of well- 

 developed pleopoda. The uropoda are single l)ranched and consist of 

 a peduncle and a l)ranch composed of a single article. The first pair 

 of legs are chelate. All the following six pairs are ambidatory. 



PANCOLUS CALIFORNIENSIS Richardson. 



Pancolus callforniensis Richardson, Proc. U. S. Nat. Mus., XXVllI, 1905, pp. 

 367-369. 



Locality. — ^Monterey Bay, California. 



Body narrow, elongate, 5^ mm. long, and almost H "ini- wide. 

 Head as wide as long, 1^ mm. : 1^ mm., with the anterior margin 

 somewhat triangular between the eyes, which are placed in the 



Fig. 1.— Pan'colus 

 califokniensis. 



X 9. 



Fig. 2.— Pancolus californiensis. Fig. 3.— Pancolxjs californiensis. a, 

 First GNATHOPOD. x 20. First antenna. x44. 6, Second an- 



tenna. X 44. 



extreme antero-lateral angles. The head anteriorly is about half as 

 wide as it is posteriorly. The lirst pair of antennte have the tirst 

 article large and robust, about half as wide as long; the second article 

 is half as long as the first; the third is a little shorter than the second 

 and terminates in a bunch of hairs. The second pair of antenna? are 

 shorter than the first, reaching only to the end of the second article of 

 the first pair of antennae The hrst article is longest, being three 

 times longer than the second; the third is about twice as long as the 



