ISOPODS OF NORTH AMERICA. 



259 



Body ovate, not twice as wide as long, 17 mm. : 28 mm., widest at 

 the fourth thoracic segment. 



The head is triangular, and at the base is wider than long, 3 mm. : 5 

 mm.; it is partly set in the first thoracic seg- 

 ment, the antero-lateral angles of which extend 

 to about the middle of the head. The eyes are 

 small, oval, composite, situated in the post- 

 lateral angles of the head, and separated ante- 

 riorly by a distance nearly equal to the length 

 of one eye. The posterior margin of the head 

 is rounded; the anterior margin is widely 

 rounded. The anterior end is 2 mm. wide. 

 The first pair of antenna? are composed of eight 

 articles and extend to the end of the sixth article 

 of the second pair of antenna?. The basal arti- 

 cles are not adjacent, being separated by a dis- 

 tance equal to 1 mm. The second pair of an- 

 tenna? are composed of ten articles, and extend 

 to the middle of the first thoracic segment. The maxillipeds have a 



FIG. 268. LIVONECA VUI.GA- 

 EIS (AFTER STIMPSON). 



FIG. 269. LIVONECA VULGARIS. a, MAXILLIPED OF FEMALE, x 27}. 6, SEVENTH LEG. x 9f. c, 

 SECOND MAXILLA, x 27. d, FIRST MAXILLA, x 27J. e, PALP OF MANDIBLE, x 27. 



palp of two articles. The palp of the mandibles is composed of three 

 articles. 



The first and fourth segments of the thorax are the longest, each 

 being 3 mm. in length. The second and sixth are each 2 mm. long. 



