106 Records of the Indian Museum. [Vol,. XXIV, 



limits of Burma. Three of these L. generosus, L. lamellatus and 

 L. scutum are confined to Burma, while the other three have a 

 much wider distribution. 



Lameliidens marginalis (Lamarck). 



1S76. ? Unio marginalis var. zonata, Hartley and Theobald, op. cit., 

 p. 20, pi. xliv, fig. 2. 



1889. Unio marginalis with vars. subflabellatta, cylindrica (nee 

 Hanley and Theobald) and obesa (nee Hanley and Theobald), 

 U. protensns var, obtusatus, Tapparonc-Canefri, op. cit., pp. 



345. 346, 350- 



1914. Lameliidens marginalis, Simpson, op. cit., pp. 1166-116S. 



1915. Lameliidens marginalis, Preston, op. cit., pp. 175, 176. 



1921. Lameliidens marginalis, Prashad, Rec. hid. Mux. XXII, p. 606, 

 fig6A. 



Ill the paper cited above I have recently given the distinc- 

 tive characters of the species and have figured the hinge of a 

 typical specimen. 



Tapparone-Canefri was apparently unaware of the great 

 variation in the shape and form of this species and gave specific 

 and varietal names to shells which are quite typical. As a result 

 of my examination of Tapparone-Canefri's named specimens I 

 find that five of his names, including his true marginalis, must be 

 treated us synonyms. Simpson doubtfully included Unio dolichor- 

 hynchus and U. gianelli in the synonymy of L. marginalis, but 

 the former on examination of the type was found to be an 

 elongate specimen of L. corrianus and the latter a half-grown 

 L. scutum. The various Burmese forms included by Preston as 

 varieties and subspecies of this. species, are discussed in the notes on 

 the several species. 



L. marginalis has a very wide range of distribution, throughout 

 India, Burma and Ceylon. 



Lameliidens corrianus (I y ea). 

 PI. II, figs. 9-11. 



1889. Unio corrianus, U. dolichorhy nchus, U. protensns and var. 



ellipticus, Tapparone-Canefri, op. cit., pp. 347-350. 

 1900. Lameliidens canefrinus, Simpson, op. cit., p. 857. 



1914. Lameliidens canefrinus, Simpson, op. cit., p. 1176. 



1915. Lameliidens canefrinus, Preston, op. cit., p. 187. 



1921. Lameliidens corrianus, Prashad, ot>. cit., p. 609, fig. 29O. 



In the paper cited above I have given reasons for considering 

 L. corrianus as a species distinct from L. marginalis. As a 

 result of my examination of Tapparone-Canefri's types of U. 

 protensus and its var. ellipticus I find, that both of them should 

 be referred to this species, Simpson's new name canefricus must, 

 therefore, be sunk in the synonymy of L. corrianus. The type 

 specimen of L. dolicJiorhynchus differs from typical shells of 

 L. corrianus in being a little more elongate and the cuneation of 

 the posterior margin is therefore more pronounced, but these differ- 

 ences in the shape of the shell in the case of a variable species 



