112 



EDWARD HULL, M.A., LL.D., T.V..S., Y.G.S., ON THE 



appeared to me conceivable, tliattlie Eocene fishes of oceanic 

 habitat may have undergone modification in their characters 

 during the gradual fresliening of the Jordanic waters. 



But the problem we have here to deal Avith is somewhat 

 different from that above stated. Besides the special ajid 

 peculiar forms above referred to, it has been shown that some 

 of the fishos and other forms (such as the crocodile) of the 

 Jordan basin are identical with those now living in the Nile 

 and other African streams entering the Mediterranean.* It is 

 needless to observe that these freshwater forms are now abso- 

 lutely isolated from each other, by the intervention of the 

 salt Avaters of the Mediterranean, as Avell as by the land 

 barrier of AVestern Palestine. Yet so considerable is the 

 number of species common to the African and Asiatic fresh 

 waters, that it can scarcely be questioned that they had a 

 common origin, and that the waters they inhabit Avere once 

 physically connected. 



In the wordsof Dr. Lortet, the crocodile has migrated along 

 Avith the papyrus from the Nile to the Zerka, and the lake of 

 Huleh is full of the African Chromis.'\ 



If this be admitted, it becomes a A^ery interesting problem 

 hoAv, and at Avhat geological period, this intercommunication 

 took place. It is a problem Avhich has long been before my 

 OAvn mind, and to Avhich I have given much thought; but it 

 is only recently that I liaA^e begun to see my Avay toAvards its 

 solution on grounds Avhich can be substantiated step by step. 



The folloAving table shoAvs the distribution of the Palestine 

 Forms as gathered from the Avorksof Lortet and Tristram : — 



* L. Lortet, Poissons et Reptiles dv, Lac de Tiheriade, Archives d« 

 Musee d'Histoire Natnrelle de Lyon, t. Ill (1883). Tristram, Fauna a;:d 

 Flora of Palestine, Mem. Palest. Exiilor. Fvind (1884 . 



t Loc. cit., 13. 122. 



