542 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Head about twice as wide as long, with the anterior margin circular 

 in outline, the posterior margin straight. The eyes are small, dis- 

 tinct, and situated on the posterior margin, at some distance from the 

 sides of the head. The first pair of antennae are short and are com- 



FIG. 584. PHYLLODURUS ABDOMINALIS. a, FIRST INCUBATORY LAMELLA, x 27}. b, MAXILLIPED. 

 x 27i. c, SEVENTH LEG. x 15|. 



posed of only three articles. The second pair are composed of five 



articles, the terminal article being tipped with hairs. 

 The seven segments of the thorax are distinct and taper gradually, 



becoming successively narrower. 

 The six abdominal segments are distinct. They taper gradually but 



rapidly to the small terminal segment which is posteriorly produced 



in a long, narrow process, which is a little longer than the basal 



part of the segment. The uro- 

 poda consist of a small branch on 

 either side of the sixth or termi- 

 nal segment and are attached at 

 the place where the basal part of 

 the segment gives rise to the long, 

 narrow terminal process. 



There are five pairs of single- 

 branched pleopoda, a pair for each 

 of the first five abdominal seg- 

 ments. They are in the form of 

 narrow, elongated sacs, rounded 

 at the extremity, and attached, one 



FIG. 585. PHYLLODURUS ABDOMINALIS. a. MALE. u -j 1 i i 



6, YOUNG FEMALE. on each slde > close to the lateral 



margin of the segments. 



The first abdominal segment bears on the dorsal surface two large 

 rounded papillae, one on either side, close to the lateral margin. 



There are seven pairs of prehensile legs. 



Dr. W. T. Caiman says that he thinks it is characteristic for the 

 males and females to be attached separately to the host. Only in one 

 case did he find a male attached to the female. The label accompany- 

 ing one male sent by Doctor Caiman reads: "Found on the second 

 pleopod of host." 



