2?X Prof. Dr. Fr. VejJovsky o?» 



by Cliilton (7, fig. 4, gn, grr) might easily lead to the 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 Crangonyx found at 

 Eadotin near Prague belongs to a distinct genus and species 

 " Eucrangonyx Vejdovsl-yi.''^ Only after comparison of the 

 original specimens from Bohemia and England, which we 

 made in Prague with Cliilfon, 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 different 

 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 Crangonyx which were collected in the course of last year 

 in great quantities in wells at Podbaba, near Prague, by my 

 energetic pujjil Herr Niessner. 



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

 main, they resemble in form the corresponding extremities of 

 Crangonyx. The little double hooks on the thighs of the 

 first and second pleopods also differ only in a small degree 

 from the same structures in other Gamraarids, especially 

 Garnmarus (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 



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

 and differs essentially in this respect from the corresponding 

 joint of the Niiihargi and Gammarids, which is armed with 

 tufts of strong seta3. 



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 Garnmarus. 1 

 must, however, remark 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 Garnmarus 

 and Crangonyx, 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 Boruta), 

 and the two-lobed telson separate Bathyonyx from the genera 



