6o4 Records of the Indian Mttseuui. [Vol.. XXII, 



shell, but the specimen from Belgaum, Deccaii (pi. xlvi, fig. 3), 

 which they consider as a link between /. occatus and /. scobina 

 does not appear to belong to either species. /. scobina has a 

 restricted range in Assam, Manipur and probably Burma, and 

 does not occur in Peninsular India. The only two specimens in 

 the Indian Museum collection are from Sibsagar, North Eastern 

 Assam, and the record of the specimens from the Manipur Valley 

 greatly extends the known range of this species. 



Most of the shells collected by Mr. S. L,. Hora from the Sik- 

 mai stream are much larger than the Sibsagar specimens ; one of 

 the largest is 2y8 mm. long, 17 mm. high and ii"5 mm. in 

 thickness. 



The animal differs from, that of the other species in having the 

 outer pair of gills shorter in both length and breadth than the 

 inner pair and in the palps being rather small. 



Indonaia theobaldi (Preston). 



1912. Nodularia {^Nodularia) iheobaldi, Preston, Rec. Ind. Mits. \'H, 

 p. 292. 



1914. Nodularia [Nodularia) theobaldi, Simpson, op. cii.,p. 1002. 



1915. Nodularia (Nodularia) theobaldi, Preston, op. cit., pp. 143, 144, 



fig. 8(1-^). 



Preston described this species from two specimens in the 

 Indian Museum collection from Manipur. The exact locality, 

 however, whence these specimens were collected is not known. 

 The species is one of the largest of the Indian forms of the genus 

 Indonaia. 



Mr. S. L. Hora collected four specimens in the Sikm^ai Stream 

 in the Manipur Valley. All these specimens, though a little 

 smaller than the type-specimen, are quite like it in other respects. 

 In all the specimens the umbones are much eroded. 



The soft parts resemble thosi of the other species of the 

 genus. None of the specimens are gravid. 



Indonaia lima (Simpson). 



igoo. Nodularia (Radiatula) lima, Simpson, op. cit., p. 820. 



1914. Nodularia (Radiatula) lima, Simpson, op. cit., p. 1018. 



1915. Nodularia {Radiatula) lima, Preston, op. cit., pp. 147, 148. 



Simpson in igoo established a new section Radiatula of the 

 genus Nodularia for the two Indian species Unio crispisulcatus 

 and Unio radnla of Benson, he also changed the name of the 

 latter to Nodularia lima owing to the specific name radula being 

 preoccupied In his later work, however, he expressed a doubt 

 as to whether N . lima did not really belong to the 7. caerulea group. 

 The sculpture of the shell of this species differs from that of the 

 type-species of the Radiatula section and is very like that of occa- 

 tus and scobina. The soft parts also resemble those of the two 

 species in all essentials. I therefore place N. (R.) lima of Simp- 

 son, with species like occatus and scobina, in my genus Indonaia. 



