18 Mr. E. J. Miers on new or little-known 



I may here observe that Dr. Stimpson has proposed to 

 separate under the name of PJatylambrus a certain number 

 of Larnbri) characterized by the excavation of the subhepatic 

 and pterygostomian regions (the excavation forming an afferent 

 branchial channel) ; but this peculiarity is developed in species 

 otherwise so dissimilar, and these species pass so completely 

 into the forms in which this channel is not developed, that I 

 think the proposed character can scarcely be retained as a 

 generic distinction. 



§ 1. Carapace usually rounded behind (the poster o-lateral margins not in a 

 line with the posterior margin) ; anterior legs greatly elongated and 

 usually spinose. (Typical Lambrus.) 



a. Merus joints of the ambulatory legs spinulose along their upper or 

 under margins, or both margins. 



Lambrus longispinus, sp. n. 



Carapace broader than long to base of rostrum, spinose and 

 tuberculate above ; there are four prominent spines in the 

 middle line, of which three are on the cardiac and one on the 

 gastric region ; in front of the latter are two smaller spines ; 

 and there are also two on the posterior margin. On the bran- 

 chial regions are several small spines, principally arranged in 

 two oblique series on each side, and one larger spine. On the 

 antero-lateral margins are about nine small, blunt, very faintly 

 laciniated teeth, increasing in size posteriorly, and on the 

 postero-lateral margins two long spines. The rostrum is 

 prominent, triangular, acute, and obliquely deflexed. The 

 anterior legs have ten or twelve spines on the anterior* mar- 

 gins of the arms, alternating in size, except the three or four 

 nearest the distal end, which are small ; also three very pro- 

 minent spines on the upper surface, and two or three on the 

 posterior margin of the arm ; on the anterior margin of the 

 upper surface of the hands are seven larger, granulated, trian- 

 angular spines and two or three smaller, and four larger and 

 three smaller on the posterior margin. The lower surface of 

 the arms, wrists, and hands is covered with rather large, 

 rounded, granulated tubercles. The merus and sometimes the 

 following joints of the ambulatory legs are compressed and 

 dentated. Length to base of rostrum about 1 inch, breadth 

 nearly 1 inch 2 lines. 



Bab. Shanghai (Jamrach). 



This species is allied to the Japanese L. validus and L. 



* In describing the species of Lambrus I have regarded the large ante- 

 rior legs as fully laterally extended; consequently the terms "anterior" 

 and "posterior" are used for the margins of these limbs, instead of 

 "inner " and "outer," the latter terms being often misleading. 



