STATE GEOLOGIST. 73 



IV. Genus Drepanothrix, Sars. 



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

 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 antennse with three ciliated setse 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 setse on the remain- 

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

 tenna? and a hook on the first foot. 



Sp. 1. Drepanothrix clentata, Euren. 



(Plate C. Fig. 14.) 



Acantholeberis dentata, edrek. 

 Drcjxinothrix setigera, sabs. 

 Drepanothrix Jmmata, saks. 



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. Genus Acantholeberis, Lilljeborg. 



Head separated by a depression from the body, with forniees 

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

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

 macula present; antennules rather long, movable, sensory setge 

 terminal, bifld 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 cffica. 



Sp. 1. Acantholeberis ciirvirosti'is, Mueller. 



Baplinia curvirostrit>, o. f. mueller. 

 Acanthocercns rigidus, schoedler, lievin. 

 Acantholeberis curvirostrh, lilljebokg, p. e. moeli^er. 



This species of a genus approximating the Lynceids has not yet 

 been fjund 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, 



