108 Wisconsm Academy of Sciences^ Arts, and Leiiers. 



GENUS 6. 

 Alonopsis. Sars, 1862. 



AcKOPERTJS, e. p. Scliodler. 

 Alonopsis. P. E. Miiller, Kurz. 



SPECIES I. 

 Plate I. Fig. 14-15. 



Alonopsis Media, sp. dov. 



Length, 0.55 mm. Heiglit, 0.35 mm. 

 Length of male, 0.4 mm. 



Eostrum prolonged and shell sharp, somewhat quadrangular 

 in shape, marked by strias. 



The dorsal margin is convex, the hinder margin nearly straight. 

 Its lower angle is rounded and without teeth. The lower margin 

 is concave, and bas long, plumose setre. The front margin is 

 strongly convex. The post-abdomen is long and slender, resem- 

 bling that of Camptocercus, and is notched at the distal extremity. 

 It has two rows of fine teeth and some small scales above them. 

 The 'terminal claws are long, slender, with a basal spine, a spine 

 in tbe middle, and are serrated. The antennules are long and 

 slender, but do not reach to the end of the rostrum. They have 

 each a flagellum and sense-hairs. The antennas are small and 

 have eight (f jf) setie and two (xw) spines. The labrum resem- 

 bles that of A. leucocephalus, but is slightly prolonged at its 

 apex. The intestine, coecum, and color resemble those of Acro- 

 perus. There is a trace of a keel present on the back. 



This species is in some retpects intermediate between A. elon- 

 gata (Sars) and A. latissima (Kurz). In general shape, rostrum 

 and marking of valves, it most nearly approaches the former, 

 while it approaches the latter in the post-abdomen, its shape, teeth 

 and armature of terminal claws. Hence I call the species A. me- 

 dia. 



