360 GAM MARION. 



This genus was founded by Rathke upon an Amphi- 

 pod taken at Balaklava, which we have not seen, but 

 which, from his description and figure, agrees so closely 

 with A. Sabinii of Leach, that we should certainly have 

 considered them as identical had not Rathke * stated 

 that they were distinct. 



The animals of this genus are essentially Arctic ; both 

 the number of species and the size of individuals de- 

 creasing as they progress southwards. The Crimean 

 species of Rathke is, however, as large as those of 

 the polar regions. 



A specimen labelled Gammarus dentatus, in the Museum 

 of the Jardin des Plantes, also so closely resembles 

 Leach's species that we should have associated them had 

 not Pondicherry been recorded as the habitat of the 

 former. 



* Nova Acta Acad. Leopold, Nat. Curios, xx. p. 71. 



