STATE GEOLOGIST. T3 



IV. GrENUS 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 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 seta on the remain- 

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

 tennas and a hook on the first foot. 



Sp. 1. Drepanothrix dentata, Euren. 



(Plate C. Fig. 14.) 



AeantholeTjeris dentata, buren. 

 Drepailbthrix setigera, saes. 

 Di'epanothrix liamata, saks. 



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

 lateralh' 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. GrENFS ACAISIHOLEBERIS, Lilljeboig. 



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. Acantlioleberiscurvirostris, Mueller. 



Baphnia curvirostrits, o. f. muellee. 

 jLeanthocercus rigidus, schoedler, lievin. 

 A.(antlioleheris curvirostrU, ltlljeboeg, p. e. mdeltjEB. 



This species of a genus approximating the Lynceids has not yet 

 been f jund 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, 



