98 XII. Karel Scháfema: 



With the speeimeiis from the other localities (lake Vrána 

 in Dalmatia, from Na renta region) this phenomenon 

 does not exist. Therefore we can distinguish the first form as 



Gammarus pungens forma carinata 

 and the second 



Gammarus pungens forma acarinata. 



7. Gam^narus pulex L. 



Gammarus pulex from the Balkán regions has more 

 dorsal si3Ínules on the uropod segments than postulated by 

 Sars and Stebbing. 



Specimens are variable according to surroundings in 

 which they live. In the lakes with plants the re are very small 

 specimens and in the lakes on stones there are living very 

 large ones of G. pulex and without plumose setae on the 

 last uropods. 



B. Gen US Carinogammarus (Stebbing) 

 contains two groups: 



a) with the dorsal produced 



t e e t h; 

 b)with an arched dorsal ca- 

 rina, without teeth. 

 a) Group with the dorsal teeth: 



1. Carinogammarus triacanthus n. sp. 

 (PÍ. I. 1; ext iig. 14, 15) 



with large eyes and the first three pleon segments produced 

 into a carinate tooth. — It li ves in the Skutari lake (leg. 

 Mrázek). 



From its neighbourhood are 



2. C afino gammarus roeselii Gerw. 

 (PÍ. I. 2; lext fig. 16, 17.) 



a form from the North and Middle Europe, but with the 

 tooth also on the 7*^ peraeon segment. 



I can corroborate the opinion of L. Keilhack (22a) that 

 >^ Gammarus tetrachanthus^^ from Muggelsee described by 



