Pacific Coast of Xorth America. 175 



c'. Ultimatesegmeotofabdomeu smooth. 

 Outer branch of uropoda but little 

 more than half as long as inner 

 branch. Sinus at extremity of ab- 

 domen small '. D. glabra, sp. n. 



It has been suggested by several authors * that Dynamene 

 may prove to be the female of JScesa, but until facts can be 

 produced to substantiate this assumption, it is necessary to 

 retain the genus Dynamene. 



21. Dynamene dilatata, sp. n. 



Body oval ; surface very granuhir ; colour yeUow. 



Head rugose, with its anterior margin produced in a 

 quadrangular process, having a small median projection, 

 rounded antero-Iateral angles, and a thickened edge. First 



Fiff. 8. 



Dynamene dilatata. 

 a, head and first thoracic segment, x 13|- ; h, dorsal view, x 10§. 



pair of antennge extend to the posterior margin of the liead, 

 tirst two joints flattened and enlarged ; first joint oblong ; 

 second joint triangular, and half as long as preceding joint ; 

 third joint small, as long as second, but half as wide ; tlagel- 

 lum six-jointed. Second pair of antennae are but little longer 

 than first pair and do not reach the posterior margin of the 

 first thoracic segment. 



The thoracic segments are of equal length. The epimera 

 are square or oblong, with straight lateral margins. 



The penultimate abdominal segment is short and crossed 

 with suture-lines. The terminal segment is triangular, with 

 a small rounded notch at the apex. There are three longi- 



* Hesse, Ann. Sci. Nat. 5th .aer. xvii. pp. 5, 6; Stebbing, Hist, of 

 Crust. 1893, p. 361 ; Bate & Westwood, British Sessile^eyed Crust, ii. 

 p. 432. 



13* 



