TERRESTRIAL AXD FLUVIATILE MGLLUSCA. 179 



exclusion of the southern species, which have not succeeded in re- 

 establishing themselves. The beautiful group Achatina, requiring a 

 degree of moisture not generally found in Palestine, is only represented 

 by a few insignificant and almost microscopic species. 



The Molluscan Fauna of this country has been less neglected than 

 other branches of its natural history. Olivier first published a few species 

 through Ferussac in 182 1. Ehrenberg added many more, of which 

 eighteen were described as new. Boissier published his list in the 

 ' Zeitschrift fiir Malakologie ' in 1S47. Bourguinat published and figured 

 in 1S53 the collection made by M. de Saulcy ; and Dr. Roth, in his 

 ' Molluscorum Species,' in his ' Spicilegium IMolluscorum,' 1855, and 

 ' Coquilles Terrestres et Fluviatiles,' edited by A. Mousson, 1861, has 

 supplied us with a catalogue far more complete and exhaustive than any 

 of his predecessors. 



But all of these contributions to our knowledge of the Molluscan Fauna 

 shrink into insignificance when compared with the magnificent work of 

 Mr. Arnould Locard, on the Fluviatile Molluscs of the Lake of Galilee : 

 ' Malacologie des Lacs de Tiberiade, d'Antioche et d'Homs,' 4to., Lyon, 

 1883. This work, superbly illustrated, gives, with the fullest details, 

 descriptions of all the known Molluscs of the Lake of Galilee, and to it 

 I am indebted for the opportunity of enumerating a great part of the 

 Unios of that unique inland sea, which contains no less than eighteen 

 species confined to the waters of the Jordan valley. One of the most 

 remarkable, and as yet unexplained, features of the phenomena of this 

 unique depression is that many of the species are found at depths of 25, 

 50, and even 100 fathoms; and some of them only at that depth. Most 

 of these deepwater species are small in comparison with the allied species 

 found in the deeper waters of other European and Asiatic rivers ; yet the 

 thickness of the shells proves that there is no want of calcareous matter 

 for their formation. The richness and brilliancy of the nacreous lining of 

 most of these shells surpasses the colouring of any European species. 



I. Limax phceniciaciis. Bourg. Test. Nov., p. 9, 1852. 



Very common in the maritime plains from Beyrout to Jaffa, and in the 

 valleys which abut on them. Not observed in the interior. Easily 

 distinguished from L. agrestis by its larger size and its crowded black 



2\ — 2 



