146 



Records of the Ivdian Mvseitm. 



[Vol. XY, 



Though the glochidia were not found in all cases to fill up all the four 

 gills, yet in P. favidens var. friportilus all the four gills were full of em- 

 bryos, and in the typical form of favidens, P. favidens var. viridula, 

 and P. corruf/ala all the four gills contained glochidia. In the other 

 varieties the structure of all the four gills was modified for a marsujjial 

 function and the absence of glochidia in some of the gills seems to be due 

 to their having been shed before the specimens were collected. 



The structure of the gills and the water-tubes is very similar to that 

 in the genus LameUidens described above. 



CL 



Fig.l. 



Glochidia of (a) L. mnrginalis var. obesa, (b) P. favidens, (c) P. favidens var. ? (d) P. 

 favidens var. assamensis, (e) P. favidens var. viridula, (f) P. currugata, (g) P. corrugnta 

 var. nag'poorensis. 



The glochidia, as will be seen from the figures (fig. 1 h — g) all of which 

 are drawn magnified 75 times, are semi-circular or semi-elliptic. In 

 their structure, sculpture of the shell and the nature of the flange on the 

 inner and lower surface of the shells they are quite like those of the genus 

 Physunio described in my paper, loc cit. 



Indonaia, gen. nov. 



Simpson in the paper cited above included in the genus Nodularia , 

 Conrad, a number of groups of shells of such wide range as Japan, China, 

 Siam, India and Africa. The anatomy of some of the members was 

 known, but the others like the Indian forms were included because of 

 the shells having a close resemblance to those of the genus Nodularia. 

 Haas^ in his account of the genus Nodularia included only the species 

 found in Siam, Cambodia, Amiam, China, the Amur region, Korea and 

 Japan, apparently considering the Indian species to belong to a distinct 

 genus. As a result of my investigations of the soft parts of the animals 

 of some of the Indian species, it was found that these species had no 

 relationships with those that proj)erly belong to the genus. Whereas 

 the species N. jajianensis (Lea), a Japanese form, and N . aequitoria 

 (Morelet), an African one. carry the glochidia in the inner pair of gills 

 (endobranchiae) and belong to the sub-family Hyrinae of the family 



' Martini iind Chcmitz, Conch. Cab., (id. Kustcr) IX, Abth. 2, pt. 2, Die Unioniden 

 (MtIO). 



