168 Records of tin- Imlion Musctnii. [VoL. XV; 



of BuUinus, but very young shells' are in some species almost indistin- 

 guishable. 



Bullinus con tortus (Mich.). 



(Plate XX, figs. 6—11.) 



1874. Ifiidura coiilorlfi, Jickoli, Nov. Act. Leo2)-Carol. Ak. Natur. XXXVII (1), 



p. 20.'J, pi. iii, fig. 4, pi. vii, fig. 14. 

 1S74. Physa (Isidora) Bruchii, var. approxinmns, Muusson, Journ. de Conch. XXI, 



p. 42. 

 1886. Physa contortu, Clcssin, op. cit., p. 314, pi. i, figs. 9-11. 

 18S(). Physa natulensis, id. ibid., p. 8, pi. i, figs. 12-14. 

 11)10. Bullinus contortus, Leiper, Journ. B. A. M. C. XXVII, p. 117, fig. 66. 



Jickeli has discussed the synonomy and Leiper proved the sanitary 

 importance of this species, which, with two closely allied forms, is the 

 intermediate host of the human parasite, Bilharzia haenuilobtmn. The 

 shell is extremely variable (see figs. 6 — 11, pi. XX) and it is possible 

 that further study will extend the synonomy. 



Specimens were obtained both in the swamp-deposit at Nasariyeh 

 and at the edge of the Euphrates at the same place ; also at Samara. 

 The shells are small, ratlier thick, and extremely variable as regards 

 both the form of the spire and the shape of the body- whorl. There are 

 shells in the Indian Museum from Portugal, Corsica, Algeria, Egypt, 

 Abyssinia, Natal and Palestine. The species is also known from tropical 

 W. Africa, from the upper waters of the Euphrates, and from Syria. 



PELECYPODA. 



Family CYRENIDAE. 



Genus Corbicula, Megerle. 

 A considerable number of species of this genus have been described 

 from Western Asia, but the synonomy of these is obscure. I have dis- 

 tinguished two forms, which seem to be specifically distinct ; others 

 I have left unnamed, 



Corbicula fluminalis (Midler). 



r.)i:5. Corbicula Jluminalis, CJcuiiuihi, Bull. JIus. ilisl. Nal. (Paris), p. 472. 



This is perhaps the commonest species of the genus in Western 

 Asia. It has a wide range in Asia and Africa. Specimens, both recent 

 and subfossil, from Nasariyeh seem to be typical. 



Corbicula cor, Lk. 



l'J14. Corbicula cor, Prcstuu, Journ. As. tSoc. Bciajal (ii. s.) IX, ]). 474. 



Specimens from Nasariyeh seem to be interijiediate between this form 

 and C. cmssula, Mousson, which is probably, as Preston points out, a 

 variety of it. They differ very little from shells from the Lake of Tiberias 

 identified by the latter conchologist as C. crassula. The species, if the 

 two be united, is common in Syria and there are specimens from Persia 



' Suu Annaiulale, Rec. hid. Mus. XIV, pi. xi, fig. 1 (i'Jl8; 



