236 Prof. Dr. Fr. Vojaovsky 07i 



by Chilton (7, fig. 4, gn, gir) niiglit easily lead to tlie view 

 that the Crangonyx found in Bohemia in a certain measure 

 represented a different species to that found in English wells. 

 Indeed Stebbing, on the ground of my representation and his 

 own experience, has considered that the Crangonijx found at 

 Eadotin near Prague belongs to a distinct genus and species 

 " Eucrangonyx VejdovsJcyi.''^ Only after comparison of the 

 original specimens from Bohemia and England, which we 

 made in Prague with Chilton, was it demonstrated, beyond 

 all doubt, that we were dealing with one and the same species, 

 in which the form of the gnathopod hands in ditferent 

 individuals is subject to a noticeable variability. 



I have been able recently to convince myself that this is 

 actually the case by an examination of numerous specimens 

 of Crango7iy.v which were collected in the course of last year 

 in great quantities in wells at Podl)aba, near Prague, by my 

 energetic pupil Herr Niessner. 



1 have not specially investigated the other feet, as, in the 

 maiuj they resemble in form the corresponding extremities of 

 Crarigoiiyx. The little double hooks on the thighs of the 

 first and second pleopods also differ only in a small degree 

 fiom the same structures in other Gammarids, especially 

 Garumarus (fig. 15). Further, the last pair of uropods 

 correspond with those of Crangonyx] they are rather short, 

 the basal joint almost as high as broad ; the outer branch 

 consists of a long proximal and a short thin distal joint 

 (fig. 12). 



The proximal joint bears on its side only one or two setae, 

 and differs essenti.dly in this respect from the corresponding 

 joint of the Niphargi and Gammarids, which is armed with 

 tufts of strong setffi. 



The inner branch is 1-jointed and reaches more than half 

 the length of the outer branch. Moreover, it is comparatively 

 longer than in JSiphargus and shorter than in Gammarus. 1 

 must, however, remaik that I have only examined these 

 uropods in two specimens. 



From the point of view of general biology the discovery of 

 Bathyonyx is very important. So far as its systematic 

 position is concerned, the genus comes between Gammarus 

 and Crnvgonyx, as it agrees with the former in its capsular 

 segmental sense-organs and with the latter in the rest of its 

 organization. Only the absence of the so-called secondary 

 gills, which are so characteristic of Crangonyx (and JBoruta), 

 and the two-lobed telson sei)i\n\te Bat/iyoiiyx from the genera 



