ISOPODS OF NORTH AMERICA. 539 



of the head. The hj^popharynx is veiy larjj'c, and just outside it is 

 seen the very oblong hiteral part of the labruni (d), the median part of 

 which is concealed by the hypopharynx. At iirst I believed that 

 these oblong organs were the mandibles, but a closer examination gave 

 the result mentioned, while the mandibles, being needles with l)rown 

 apex, were discovered within the rostrum. .Maxilluht? are not 

 observed; the maxillie (/') are small semicircuhir lobes h'ing consid- 

 erably behind the posterior edge of the labrum. The maxillipeds ((/) 

 ar(^ short, extremely slender, almost styliform. 



"Thorax: The segments are rather convex, the incisions between 

 them comparatively broad and very deep; the lateral margins are much 

 curved when seen from the side. The legs increase considerably in 

 length and very much in thickness from the Iirst (tig. 581c) to the liftli 

 pair (tig. 5816?), which is robust, with the hand very large; the two 

 poterior pairs again decrease somewhat in size. The terminal mar- 

 gin of the hand is deepl}^ concave, thus differing considerably from 

 the preceding forms. 



"Abdomen: It occupies scarcely one-fourth of the length of the 

 animal; it is narrower than the last thoracic segment, shortly ovate in 

 outline, without the slightest rudiment of segmentation or abdominal 

 feet; both the ventral and especially the dorsal surface are very 

 convex. 



"Size: Uncommoid}' large, being 7 mm. long and 2.3 mm. broad.'' — 

 Hansen.^ 



91. Genus PHYLLODURUS Stimpson. 



"Femina? pedes thoracis sat validi, toti ancorales, nnguiculati; 

 appendicibus branchialibus carentes. Appendices abdominis ])ran- 

 chiales; superiores laterales, laminis duabus acquis magnis elongatis; 

 inferiores papilliformes. Abdominis segmentns primus setis dorsali- 

 bus unguiculatis instructus." — Stimpson.* 



Abdominal parasites. 



Body of female is almost S3"mmetrical. 



Ovarian bosses present. Posterior portion of lateral margins of tho- 

 racic segments not produced. Epimera present on all the segments, 

 not distinctly separated on the last two; the}' occupy the anterior part 

 of the lateral margin on the first four segments; on the fifth segment 

 they are placed between the anterior and posterior divisions of the seg- 

 ment; on the last two segments they occupy the posterior portion of 

 the lateral margin. 



The abdomen is distinctl}' segmented, becoming gradually and rap- 

 dly narrower from the first to the terminal segment; lateral parts of 

 segments or pleural lamellae not developed. On the dorsal surface of 



a Bull. Mus. Comp. Zool. Harvard College, XXXI, 1897, pp. 122-124. 

 &Bost. Journ. Nat. Hist., VI, 1857, pp. 511-513. 



