858 Puget Sound Mariiie Sta. Pub. Vol. 1, No. 30 



Family GRAPSIDAE 

 Genus Hemigrapsus 



KKY TO SPECIKS 



A. Legs sinootli and free from Iiairs; liands spotted. 1. //. nudus 



AA. Legs sinootli hut hairy; hands not spotted. 2. //. o?-('c/ourn.s-is- 



1. Hemigrapsus nudus (i)ana) Rathhun. purple shoke crab 



(fk;s. 1. 2, 3, 9) 



Pseudograpsus nudus Dana; Ileierograpsus nudus Stiinjjson ; Ilctero- 

 grapsus sanguineus Kingslev; Brachi/uotus nudus Holmes. 



Rostrum none. Antennae short, ineonspieuous. Carapaee roughly 

 rectangular, anterior part eonvex and undulated ; jxjsterior margin straight 

 except at each end where it is concave to make a place for the attachment 

 of the last pair of walking legs; front of 2 lobes with comparatively 

 broad and shallow emargination ; the 2 prominences behind the front about 

 evenly rounded; 3 teeth on the anterior lateral margin counting the post 

 orbital one as the first, first 2 markedly convex, the last very much smaller 

 and less prominent than the others ; surface of the carapace smooth, punc- 

 tate, curved line of white pits from the H-shaped depression in the center 

 to the last antero-lateral tooth. The line of teeth or granulations on the 

 pterygostomian region run practically parallel to the antero-lateral mar- 

 gin and are larger and farther a))art on the posterior end of the line. 

 !Maxillipeds ])unctate with round edge on inner margin of ischium and 

 merus. Chelipeds large, powerful; merus trigonous with rounded projec- 

 tions at distal end; carpus with prominent projection on inner surface; 

 hands sinooth, inflated; fingers toothed; large patch of long soft hairs on 

 the inner ])alms of the eheli})e(ls of the males. Predominating color red- 

 dish purple flecked with dirty white; hands always s))otted. 



Often great variation in color is noted; some are green and black 

 without any indication of purple, while others are reddish brown; often 

 there arc large irregular spots of dirty white on the carapace and in 4 

 instances the whole carapace save for a tiny sjjot on the posterior margin, 

 was dirty white. This great variation in color and markings was noted 

 only among the smaller specimens, yet many of these were sexually mature 

 and were carrying eggs. One of those bearings eggs was 15 mm. wide 

 and 14 mm. long; the carapace of the largest found was 37 mm. long, 41 

 mm. wide. They are abundant everywhere along the shore below the high 

 tide line. Some hide und(-r rocks and stones and others run about under 

 the algae out from the shore. On several occasions they were found on the 

 piles under the Friday Harbor docks (4). 



