ISOPODS OF NORTH AMERICA. 



628 



long as the fourth. Th(^, ilagellum i.s composed of two unequal arti- 

 cles, the first one being- the shorter. The second antennae extend to 

 the middle of the third thoracic segment. The maxillii)eds have a palp 

 of three articles. The palp of the mandil)les is wanting. 



The segments of the thorax are subequal. There is no indication 

 of epimera on an}" of the segments. 



Fig. 671.— Porcellio scaber (After Sars). a, Mandibles, b, First antenna, c, Dorsal view 

 OF FEMALE, d, Second antenna, e, Anterior lip. /, Second maxilla. </, First maxilla, h, 

 Mandible, i, Posterior lip. j, Last segment of abdomen and uropoda. k, Uropod. I, Max- 

 ILLIPEDS. m, Head, n, First pleopod of female, o, Second pleopods of male, p, Var. mar- 



MORATA (dorsal VIEW OF FEMALE), q, FiRST PLEOPODS OF MALE, r, TUIRD PLEOPOD OF MALE. 



s. Abdomen (ventral view). 



The abdomen is as wide as the thorax. The first two segments are 

 covered at the sides by the lateral parts of the seventh thoracic seg- 

 ment. The sixth or terminal segment is li mm. wide at the base. It 

 is triangularly produced to a long, narrow extremity, which is posteri- 

 orl>' rounded. The terminal segment is 1 mm. long. The uropoda 

 are longer than the terminal segment. The outer branch extends i 



