STATE GEOLOGIST. 73 



IV. Ge]S"US Drepanothrix, Sars. 



The head not separated from the valves by a depression; fornices 

 moderate; rostrum rather acute, distant from the anterior edge of 

 the valves. The form is subrotund; reticulate, with the margins of 

 shell fringed below by long movable spines; pigment fleck present; 

 swimming antennae with three ciliated setae on the 4-jointed ra- 

 mus, the 3-jointed ramus with its basal joint armed with an un- 

 jointed, strong, spinous seta and four ciliated setae on the remain- 

 ing joints. The post-abdomen is broad. The male has longer an- 

 tennae and a hook on the first foot. 



Sp. 1. Drepanothrix dentata, Euren. 



(Plate C. Fig. 14.) 



Acantholeheris dentata, ^VRBS . 

 Drepanothrix .setig era, saks. 

 Drepanothrix hamata, sars. 



This animal is only 0.5 mm. in length. The antennules are 

 laterally curved in the middle and ornamented with notches on the 

 margins; the pigment fleck is quadrate and rather large; the post- 

 abdomen is truncate at the end, convex behind and ornamented 

 with a series of small spines. Only found in Scandinavia as yet. 



V. GrENUS x^cANiHOLEBERis, Lilljeborg. 



Head separated by a depression from the body, with fornices 

 above the base of the swimming antennae; rostrum erect, rather 

 acute; shell oblong, truncate behind, ciliate below with long setae; 

 macula present; antennules rather long, movable, sensory setae 

 terminal, bifid at the apex. 



The tri-articulate ramus has a long spiny seta on the basal joint; 

 feet six pairs; no abdominal process; post-abdomen wide, large; in- 

 testine without caeca. 



Sp. 1. Acantlioleberis curvirostris, Mueller. 



Baphnia curvirostris, o. f. mueli^er. 

 Acanthocercus rigidus, schoedler, lieviI'J'. 

 Acantholeberis curvirostris, lilljeborg, p. e. mubller. 



This species of a genus approximating the Lynceids has not yet 

 been found in America but is to be expected. 



The abdomen is rounded toward the end and spiny posteriorly; 

 the terminal claws are furnished with two strong teeth at the base, 



