544 THE NATUEAL HISTOllY llEVIEW. 



species are identical with, or similar to those of the Nile and of the 

 Euphrates ; and some of the genus Melanopsis are peculiar to the 

 Jordan or its feeders. It seems probable that the inhabitants of the 

 waters were better able to sustain the cold of the glacial epoch than 

 the molluscs of the land ; and from the post-tertiary remains found 

 by the Dead Sea, we may infer that the species now existing have 

 been transmitted from a period antecedent to the glacial ; while the 

 more boreal forms introduced at that epoch have maintained their 

 existence in the colder districts of Northern Palestine to the 

 exclusion of the southern species, which have not succeeded in 

 re-establishing themselves. The beautiful group Achatina, re- 

 quiring a degree of moisture not generally found in Palestine, is 

 only represented by a few insignificant and almost microscopic 

 species." 



The remaining parts of the collection made by Mr. Tristram's 

 expedition are, we are informed, in the hands of different Natu- 

 ralists, who have undertaken to work them out in a similar manner. 

 "When this has been accomplished, Mr. Tristram proposes to 

 combine the whole in a special publication to be issued by the Eay 

 Society, under the title of " A Synopsis of the J'auna and Plora of 

 Palestine." 



