58 Records of the Indian Museum. [VoL. XVIII, 
Corbicula fluminalis (Miiller). 
(Pl. viti, figs. 1-6.) 
4. Tellina fluminalis, Miller, Verm. terr. et fluv. Hist. \I, p. 205. 
8. Cyrenacor, Lamarck, Anim. sans. Vert. V, p. 552. 
4. Cyrena crassula, Mousson, Bellardi’s Cat., p. 54 
4. Corbicula cor, Prime, Ann. Lyc. Nat. Hist. N. York, VIII, p 7, 
fig. 8. 
1866. Corbicula ecrassula, id., ibid., p- 216, figs. 44, 45. 
1883. Corbicula fluminalis+C. crassula, Locard, Arch. Mus. Hist. Nat. 
Lyon III, pp. 222, 256, 258, pl. xxi, figs. 17, 18, 25, 26. 
1913. Corbicula fluminalis, with var. cor, Germain, Bull. Mus. Hist. Nat. 
(Paris), p. 472. 
The species is a very variable and plastic one and has a very 
wide geographical range in Africa and Asia. It was originally 
described from the Euphrates. We have examined a large series 
of fresh and subfossil shells from Seistan, the Afghan desert and 
Northern Baluchistan. Those from the Afghan desert were col- 
lected by the Seistan Boundary Commission of 1902-1903. Several 
small shells were also obtained in a spring of distinctly brackish 
water at Saindak in the west of the Baluchistan desert. In most 
of the series comprised in this collection, including those of fresh 
shells from the Hamun-i-Helmand, the specimens can be separated 
easily enough into two groups, one agreeing well enough with the 
majority of sheils from the Euphrates, the other with the breadth 
proportionately narrower and the umbonal region more prominent. 
The former form is undoubtedly the true Tellina fluminalis of 
Miiller, while the latter agrees closely with Prime’s figures of 
Corbicula cor (amarck). In one large series from the desert on 
the banks of the Helmand in Afghan territory some of the shells 
are still narrower and come very near the same author’s figures 
of Corbicula crassula, Mousson; while in several series shells inter- 
mediate between C. fluminalis and C. cor, C. cor and C. crassula 
are readily selected. C. cor and C. crassula may, therefore, be 
recognized at most as varieties, if this be convenient, but not as 
distinct species. 
All the shells we have examined from Mesopotamia, Seistan 
or Persia are small, and the species in Asia Minor (in which also, 
however, it is (fide Locard) plastic in size) apparently attains larger 
dimensions in favourable circumstances. The largest fresh speci- 
mens we obtained in Seistan is a single valve 27°5 mm. broad 
by 24°5 mm. high. It exhibits an interesting abnormality in the 
hinge, in which only one, the central, cardinal tooth is developed. 
The colour of the periostracum varies from bright green to black ; 
that of the inner surface is violet. Mesopotamian shells are often 
decorated with broad, whitish, transverse bars externally. 
The species commonly hides itself in mud or sand in winter. 
We found very few living examples in Seistan, in spite of the 
abundance of fresh shells everywhere. Several living individuals 
were, however, dug from mud at the bottom of small pools in the 
Randa stream near Jellalabad, about 12 miles north of Nasratabad, 
in November. 
