XX. FRESHWATER SHELLS FROM MESOPOTAMIA. 



By N. Annandale, D.Sc, F.A.S.B., Director, 

 Zoological Survey of India. 



(With Plate XX.) 



The shells discussed in this paper were found for the most part in 

 what may be called a subfossil condition. Some of them may now be 

 extinct in the districts in which they were collected, but this seems to 

 be improbable in most cases, and some have certainly been deposited by 

 recent inundations. The collection was made at two localities ; in the 

 neighbourhood of Nasariyeh on the Euphrates, near where it now joins 

 the Tigris, and at Samara on the latter river. For most of the speci- 

 mens I have to thank Lieutenant-Colonel W. H. Lane, whose valuable 

 notes have been of great use in considering the environment in which the 

 different species lived ; for others I have to thank Bombardier E. 

 Hodgart, who in civil life is a collector attached to the Zoological Survey 

 of India, and while on active service has not neglected to obtain speci- 

 mens for presentation to the Indian Museum. 



The specimens from the neighbourhood of Nasariyeh are from three 

 different deposits probably of different age but in no case of great geo- 

 logical antiquity. Some are from a place annually inundated by the 

 Euphrates, others from an almost superficial deposit now separated 

 from the bank of the river but once probably the bed of a poOl or back- 

 water connected with it in the floods if not perpetually, while others 

 again are from the bed of a shallow lake that has been filled from time to 

 time with sand. There is some evidence that this last deposit was 

 laid down in water that was or had recently been bracki.sh. The 

 specimens from Samara were found in the dry bed of an ancient tank 

 and all the shells are white and opaque. Amongst the freshwater 

 forms I found a number of mone}'" cowries {Cypraea (Aricia) nionefa , L.), 

 the presence of which is evidently fortuitous and due to man, and also 

 shells of at least two species of Helicidae, which I shall not attempt to 

 name. 



The shells from the most recent deposit on the banks of the Euphrates 

 at Nasariyeh belong to the following species : — 



Gastropoda. Pelecypoda. 



Neritina jordnni Corhicida fluminalis 



Melania tuhercidata Corhicida cor 



Melanopsis nodosa JJnio calliopsis 



Limnaea spp. Unio tigridis 



Planorbis convexiuscuhis Unio ciconius 



Bullinus contortus Gahillolia euphratica 



All these shells, except those of the Unionidae and Cyrenidae, are 

 for the most part white and opaque. Some of those of Pulraonates, 



f2 



