i8o 



HARDWICKE'S SCIENCE-GOSSIP. 



ON BRITISH FRESH-WATER MITES. 

 By C. F. George. 



[Continued from j>age 82.] 



EXT to Arrenurus, I shall deal with the sub- 

 family Atax. There is some confusion about 

 the term Atax, in consequence of different writers 



N 



mandibles alone, but as these organs differ consider- 

 ably in different species of Atax, they would not by 

 themselves serve to separate them readily from all 

 the other sub-families ; the front pair of legs are, 

 however, sufficiently peculiar to answer that purpose. 

 They are, as a rule, somewhat thicker than the other 

 legs, and bent almost like the blade of a scythe ; but 

 the characteristic part is, that they have very strong 



Fig. 114. — Tore-leg of Atax (magnified), showing swimming thorns. 



Fig. 116. — Sexual discs. 

 I objective. 



Fig. 115. — Mandibles of Atax (mag.). 



applying the word to mites belonging to different 

 families ; I shall, however, use it to signify creatures 

 so called by Koch ; these are numerous in species, he 

 having described twenty-one, a little more than half 

 the number attributed by him to Arrenurus. They 

 would easily be distinguished from Arrenurus by the 



Fig. 117.— Sexual discs. 

 I objective. 



and rigid swimming bristles attached to projections 

 in such a manner that, when the creature uses these 

 legs in one direction, these bristles or thorns shut up 

 like the blade of a knife, and, on the contrary, whilst 

 making the effectual stroke in the other direction, 

 they remain rigid at right angles ; one can under- 



