618 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



The segments of the thorax are subeqnal in length. The lirst one 

 has the antero-lateral angles produced to surround the head, and they 

 extend almost to the base of the antero-lateral angles of the head. 

 The epimera are perfectl}^ united with the segments. The lateral mar 

 gins are straight. 



b 



Fig. 668.— Porcellio rathkei (After Sars). n, Dorsal view of male. 6, Dorsal view of 

 FEMALE, c, First antenna. </, Seventh le(;. e, Maxilliped. /, Last segment of abdomen 

 AND UROPODA. g. First pleopod of male. /;, Flagellum. i, Uropod. j, Second antenna. 



All six segments of the abdomen are distinct, the first two having 

 the lateral parts covered by the seventh thoracic segment. The third, 

 fourth, and fifth segments have the lateral parts produced so as to con- 

 tinue the oval outline of the body. The sixth or terminal segment is 

 triangular with apex produced in a long, narrow process. The length 

 of the segment from the base to the extremity of the apex is equal to 

 its width at the ))ase, 1 nmi.: 1 nun. Tht^ peduncle or basal article of 



