I8OPODS OF NORTH AMERICA. 



295 



by the relative length of the uropods, the outer branch being only 

 half as long as the inner one, while in E.i-i>*]>lt;ri'oma dm/esl both 

 branches are of nearly equal length, and by the difference in color. 

 Type. Cat. No. 19609, U.S.N.M. 



EXOSPHjEROMA DUGESI (Dollfus). 



Rphteroma dugesi DOLLPPS, Bull. Soc. Zool. France, X VIII, 1893, p. 115, figs. 1-2. 

 Locality. Mexico (fresh water); Eaux thermales d'Aguas-Calientes, 

 etat d'Aguas Calientes; Mexico. 



FlG. 313. EXOSPH.EROMA DUO ESI (AFTER DOLLFUS). a, HEAD AND FIRST THORACIC SEGMENT. 

 6, ABDOMEN AND UROPODA. 



Body ovate, twice as long as wide, 6 mm. : 12 mm. 

 Head twice as wide as long, 2 mm.: 4 mm., with a frontal border 

 arising between the eyes and produced in a small median point. 



FIG. 314. EXOSPH.EROMA DUGESI. a, MANDIBLE, x 41. 6, FRONTAL LAMINA AND CLYPEPS. 



c, MAXILLIPED. x 41. 



x 23. 



Eyes small, round, composite, and situated in the post-lateral angles 

 of the head. The basal article of the first pair of antennae is long; the 

 second is half as long as the first; the third is one and a half times 

 longer than the second. The flagellum is composed of eight articles. 

 The first antenna? extend to the middle of the first thoracic segment. 



