ISOPODS OF NORTH AMERICA. 



451 



Baltic Sea; North Sea; (lermany; west coast of lleloohuul; Kuiiniaro, 

 Stockholms skargard (J. Ijindahl). 



Depth. — Found on surface in tide pools; low water, under stones. 



Bod}^ oblong-ovate, twice as long as wide, I2 nun. :o nun. 



Head about twice as wide as long, with the anterior margin produced 

 in the middle in a large rounded lol)e. Lateral margins straight, with 

 the post-lateral angles round, the antero- 

 lateral angles not produced. The eyes 

 are small, oval or round, composite, and 

 dorsalU' situated. The tirst pair of 

 antennae have the first article large; the 

 second and third are aV)out equal in 

 length and a little shorter than the first. 

 The flagellum is composed of two articles. 

 The second pair of antenna^ have the 

 first four articles short and subequal; 

 the fifth article is twice as long as the 

 fourth; the sixth is one and a half times 

 longer than the fifth. The fiagellum 

 is composed of about eighteen articles. 

 The second antenna' are short, not reach- 

 ing beyond the posterior margin of the 

 fifth thoracic segment. The maxillipeds 

 have a palp of five articles. The palp 

 of the mandibles is composed of three 

 articles. 



The lateral margins of the thoracic segments are straight and not 

 produced into lobes. The epimera are not separated ott' from the 

 segments. 



The abdomen is composed of a single large segment, rounded pos- 

 teriorly, with a small median excavation for the reception of the 

 uropoda. The uropoda are short, not extending beyond the extremity 

 of the abdomen, and situated within its posterior excavation. The 

 outer branch is a little smaller and shorter than the inner branch. 



All the legs are ambulatory, with tri-unguiculate dactyli. 



J^RA WAKISHIANA Spence Bate. 



Jxra ivakiskiana Spexce Bate, Lord'8 Naturalist in British Columbia, II, 1886, p. 

 282.— C. BovALLirs, Bihang till K. Sv. Vet.-Akad. Handl., XI, 1886, No. 15, 

 p. 49.— RiciTARnsoN, Proc. U. S. Nat. Mus., XXI, 1899, p. 857; Ann. Mag. 

 Nat. Hist. (7), IV, 1899, p. 323; American Naturalist, XXXIV, 1900, p. 298. 



Locality. — ^JEsquimault IIarl)or, British Columbia. 



''Posteriorem marginem plconis habens bisexcavatum cuspide inter- 

 media supra cuspidatos margines non producta; antenna? inferiores non 

 possunt extendere supra quintum segmentiun: pereionis posteriora ple- 

 opoda non longiora quam posteriori margo latus est. 



Fig. 504. — JjiKA marixa. a, Maxilli- 

 PED. X 77i. &, Mandible, x 77^. 



<•, ABDOMEN WITH UROPODA. X 41. 



