168 Proceedings of the Biological Society of Washington. 



surface. Telopodite of posterior gonopcds a rather slender, strongly 

 chitinous, curved blade with broader basal region extended rnesad; the 

 telopodite much larger than in Onychelus and Hesperolus; at apex simply 

 notched or with a small angle or tooth just proximad of the rounded apex. 

 First two to four pairs of legs of male crassate and with the claws hyper- 

 trophied; other anterior legs with claws normal in size. Coxae of third 

 legs of male with conspicuous, simple, subcorneal processes which do not 

 exceed in size those of the coxae of the next four pairs. Mesal margins 

 of anal valves meeting in a groove. 

 Genotype. — A. californicus, sp nov, 



Atopetholus californicus, sp. nov. 



General color brown with an annulus of black a little in front of caudal 

 margin of each segment, the color along which remains light; legs dark 

 brown, more fulvous proximally. Anal scutum and valves dusky or black. 

 Collum also dusky, somewhat paler in median region. Sulcus of head 

 complete, not interrupted. Setigerous foveolae, 5 + 5. Antennae reach- 

 ing to third segment. Collum strongly narrowed ventrad, the lower end 

 acute; margined in front up to level of eye on each side; anterior margin 

 slightly concave opposite each cardo. Second segment on a level below 

 with lower end of collum in male, often exceeded by latter in female. 

 Segments furrowed along position of suture, which is not itself distinct. 

 Several transverse striae in front of position of suture, the most caudal 

 of these especially well marked and taking its origin low down on the side 

 from the suture proper. Metazonites lightly finely punctate, the pro- 

 zonites more vaguely so. Anal valves broadly convex, not compressed, 

 caudally flattened. Claws of first two pairs of legs of male as long as last 

 tarsal joint; those of other legs smaller, of normal or nearly normal size. 

 Number of segments, forty-eight. 



Length (male), near 52 mm.; width, 5 mm. 



Locality. — California: Claremont. (W. A. Hilton.) 



Atopetholus parvus, sp. nov. 



Easily distinguishable, aside from coloration, much smaller size, etc., 

 by the different structure of the gonopods of male A conspicuous feature 

 in these is that the telopodites of the posterior gonopods are much larger 

 and protrude widely beyond the anterior gonopods, being bent caudad 

 below and beyond telopodites of latter. The anterior median plate is 

 similar but is distally narrower and extends farther distad. The telo- 

 podite of anterior gonopods shorter than in the genotype, somewhat 

 semicircular in outline with the process arising from the distal edge, 

 not from the mesal edge. Segments in general blackish; a narrow light 

 stripe along caudal margin of each segment, especially in anterior region; 

 the prozonites on sides and in a spot just above level of pore may be 

 areola ted with numerous small light dots. Collum over median region 

 with a close network of dark lines over a fulvous background, a sub- 

 marginal band of black all around ; legs fulvous ; anal scutum black except- 



