280 WOLCOTT, [VOL. I. 



I. A. pcctinatus n. sp. 



Related to both A. crassipes (Miiller) and A. figuralis (Koch), 

 and bearing resemblances to each, but rather closer to the 

 latter than to the former. Of the form of A. fignralis, but 

 smaller, the males averaging .7 mm., the females .8 mm. in 

 length ; legs somewhat shorter, the first pair shorter than the 

 body, the second and third about one fourth longer, and the 

 fourth two thirds longer. No spines on first pair of legs set 

 into the side of projecting sockets, and all the spines shorter 

 than those of A . figuralis . Palpi much thicker than first pair 

 of legs and very long, equalling one third the length of the 

 body ; chitinous papillae one fourth segment short. Claw of 



first pair of legs peculiar, being expanded 

 dorso-ventrally and flattened laterally, form- 

 ing a broad plate, the ventral margin of 

 FIG. i. --/j. pectinatus w hj c h j s deeply pectinate, thus suggesting 



$ distal segment L * 



first pair of legs. the specific name (Fig. i). Claws of the 

 other legs long, slender, and simple. Sexual 

 area of female similar to that of A. crassipes, three acetabula 

 on each of four plates ; in the male the two plates on either 

 side united into one, upon which the six acetabula are 

 arranged in two groups of three. 



A free-swimming form, of which six specimens were dredged 

 in Lake St. Clair, Mich., over a bed of Chara, at depths of from 

 six to twelve feet. 



II. A. abnormipcs n. sp. 



A small species, the body of the male pyriform in shape, 

 deeply emarginate posteriorly, .5 mm. long ; of the female very 

 slightly pyriform, with the posterior margin rounded, .6 to .7 

 mm. long. Surface of the body marked by lines dividing it 

 into minute hexagonal areas. Palpi rather slender, somewhat 

 less than half the length of the body, with a long fourth seg- 

 ment and a broad fifth segment, the lateral surface of which is 

 quadrate in outline with the ventral distal angle produced, and 

 the distal margin with two curved claw-like projections (Fig. 2). 



