22 BIOLOGICAL SURVEY OF 



GAMMARIDAE 



Cheirocratus hlgelowi spec. iiov. (fig. 11) 



Male: The general appearance of this species is similar 

 to that of the others of the genus. Only the first segment of 

 the urosome (fourth pleon segment) has a dorsal mucro. 

 This mucro has a spine at each side. The next segment also 

 bears a pair of dorsolateral spines. The first side plate has 

 the inferoanterior corner produced and pointed. The sec- 

 ond gnathopod has the dactyl closing medial to the oblique 

 palm. The dactyl is slightly toothed at the beginning of the 

 distal third. The seventh pereiopod has the fourth to sixth 

 segments not wider than the same segments of the fifth and 

 sixth pereiopods. The third abdominal epimere has a distinct 

 notch immediately above the inferoposterior corner. 



Female: The dactyl of the second gnathopod closes lat- 

 erally. The hand is smaller and proportionately narrower 

 than in the male. The palm is very oblique, ill-defined, and 

 slightly concave. 



Length : Male, 15 to 20 mm. ; female, 10 to 15 mm. 



Type : Male, B 156 ; cotypes, B 108. 



Eemarks: This handsome species is dedicated to my 

 friend and teacher. Dr. Robert P. Bigelow, of the Massachu- 

 setts Institute of Technology. 



The animal is strikingly marked with red and white stripes. 



Cheirocratus sundewalli (Rathke) may be taken as the 

 nearest relative of the present species. C. higeloivi differs 

 from it in the form of the first side plate, the epimere of 

 the third abdominal segment, and the lack of a mucro on the 

 fifth abdominal segment, as well as in more minor points. 



