522 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



rounded process developed at the anterior end. These processes are 

 almost rudimentary on the other side. 



All six segments of the abdomen are distinct. The lateral parts of 

 the first five segments are well developed. The sixth or terminal seg- 

 ment is small, and has the lateral parts not developed. The uropoda 

 are simple, single-branched, and consist of two elongated lamelhe. 

 The pleopoda are five pairs of double-branched 

 lamella, which are elongated and tapering, leaf-like 

 and covered with tubercles. The ventral side of the 

 first five abdominal segments has the posterior margin 

 produced into numerous small elongated processes. 



There are five pairs of incubatory lamellte, which 

 do not completely inclose the marsupial cavity. 



The legs are all similar and prehensile, and have 

 no carina? on the basis. 



The male is 4A^ mm. long (not including the uropoda) 

 and li mm. wide. The head is without eyes and has 



Fig. 668.— CRYI'TIONE - i ■? i i • • l i J 1 rrM, Jl j- 



ELONGATA (After tnc irontal margin widely rounded, ihe first pair 

 Hansen). Dorsal of antenna^ are composed of three articles. The 



VIEW OF MALE. J • i- i. ^ 4^ • ^ 4- i-- ^ 



second pair ot antenna? are composed or eight ai"ticles, 

 the last four being minute and rudimentary. 



All seven segments of the thorax are distinct. The seven pairs of 

 legs are prehensile. 



All six segments of the abdomen are distinct. The sixth or termi- 

 nal segment has the post-lateral angles produced in an elongated proc- 

 ess on either side, Avhich probably represent the uropoda. Between 

 the uropoda the posterior margin of the terminal segment is triangu- 

 larly produced. There are five pairs of simple sac-like pleopoda. 



87. Genus PSEUDIONE Kossmann." 



Body of female oval, somewhat asymmetrical. 



Segments of a])di)men distinct. Epimera well defined, not contigu- 

 ous. Lateral parts of abdominal segments lamellar, more or less 

 projecting. 



Terminal segment of abdomen small, with sides not lamellarly 

 produced. 



Incul)atory plates meet in the median ventral line, concealing the 

 incubatory pouch and the eggs; first pair with the distal segment 

 usually produced in a lobe. 



All seven pairs of legs present. Pleopoda well developed, double- 

 branched. Uropoda simple, consisting of a pair of lanceolate Iamella\ 



Male with the segments of thorax and abdomen distinct. Pleopoda 

 present in the form of five pairs of small rudimentary sac-like bodies, 

 a pair for each of the first five segments. The uropoda are w'anting. 



Branchial parasites. 



«See G. O. Sars for characters of genus, Crust, of Norway, 11, 1899, pp. 200-201. 



