620 



Records of the Indian Museum. [Vol. XXII, 



Planorbidae. 



i8. Indoplanorbis exustus (Deshayes). 



19. Gyraulus convexiusculus (Hutlon). 



20. Gyrahis cantori (Benson). 



21. Hippeiitis (?) umhilicalis (Benson). 



22. Segmentina calathns (Benson). 



23. Caniptoceras lineatiim, Blanford. 



Ancyudae. 



24. Ancylus {Ferrissia) viola, Annandale and Prashad. 



25. Ancylus (Ferrissia) verruca, Benson. 



26. Ancylus {Ferrissia) ceylanicus, Benson. 



PELECYPODA. 



Unionidae. 



27 

 28 

 29 

 30 

 31 

 33 



33 

 34 

 35 



Indonaio occatn (Lea). 

 Indonaia boniieandi (Simpson). 

 Indonaia scohina (Hrinlej). 

 Indonaia theohaldi (Preston). 

 Indonaia lima (Simpson). 

 Lainellidens marsinalis (Lamarck 

 Lamellidcns consobriniis (Lea). 

 Lamellidem corrianus (Lea). 

 Trapezoideus misellus (Morelet). 



Cyrenidae. 



36 

 ?,7 

 38 



39 

 40 



41 

 42 



Corbiciila occidens, Deshayes. 

 Corbicula striatella, Deshayes. 

 Corbicula subradiata, Prime. 

 Sphaeriuni indicuni, Deshayes. 

 Sphaeriiiin aiisteni, Pra.shad. 

 Pisidium clarkeanum, G. and H. Nevill. 

 Pisidium hydaspicola, Theobald. 



Twenty-two genera and subgenera are mentioned in this Hst 

 of fortj'-two species. Of the genera and subgenera only six call 

 for any special comment, the remaining fourteen being of wide and 

 general distribution in the Oriental Region if not over the whole 

 world. The six are Alocinma (subgenus of Amnicola). Digonio- 

 sloma, Lecythoconcha , Camptoceras, Indonaia and Trapezoideus. The 

 first of these is known from Mesopotamia Seistan, all parts of 

 Peninsular India, Upper Burma and Manipur. Its headquarters 

 are in Peninsular India. The genus Digoniostoma has recently 

 been described to contain certain Peninsular Indian species. It is 

 common all over India proper and .A.ssam , but has not been found 

 west of the Indus or in Burma. Lecythoconcha, on the other hand, 

 is an eastern genus, the range of which extends from Manipur (and 



