1866. ] Contributions to Indian Malacology. 151 
correct position of these species, if the hinge teeth are trustworthy 
indicators of generic affinity. H. and A. Adams, in the Gen. Ree. 
Moll., include under Monocondylea, M. Vondenbuschiana, Lea, from 
Java,* described by Lea as a Margaritana (Baphia of Adams) and 
several species of the genus have been described from Siam and 
Cochin China by French and American naturalists. 
I have received from Mr. Theobald fine specimens obtained in Pegu 
which correspond admirably with Margaritana Vondenbuschiana, Lea, 
and unquestionably belong, I think, to that species; and also shells 
which appear to belong to a variety of Anodonta inoscularis, agreeing 
with the type in size, shape and every character of importance; and 
not only are the two forms unmistakeably congeneric, but I even 
think it probable that specimens might be met with to unite them 
specifically, as they differ in no essential character, except the very 
different degree of development of the cardinal tooth, which in 
Vondenbuschiana is scarcely raised, while in the specimens which I 
refer to inoscularis it is sometimes nearly a quarter of an inch high. 
There are in the Asiatic Society’s collection, also, two forms which 
appear to me certainly varieties of M. Vondenbuschiana. One of them, 
however, agrees more closely with the figure of MZ. Cumingir, Lea 
(Jour. Acad. Nat. Sci. Phil. 2nd Ser. IV, 235, pl. 33, f. 114) a Ma- 
lacea shell, which only differs from Vondenbuschiana in unimportant 
minutie, 
M, Vondenbuschiana is described and figured by Lea in Trans. Am. 
Phil. Soc. VIII, 222, pl. 18, f. 39, and also in Kister. 
Were there nothing but the form of the hinge teeth to connect the 
South American species of Monocondylea with the Burmese and Java- 
nese Pseudodon and Margaritana, especially having regard to the very 
diverse form of the shell, I should suspect them to be in reality distinct 
types. But there is one little peculiarity which appears to tend to 
unite them, At the termination of the portion of the hinge line in 
which, by close inspection, flattened obsolete representations of the 
lateral teeth may be seen, there is a very peculiar expansion of the 
end of the ligament which covers a small sinus in the inner surface of 
both valves. This is very well shewn in Lea’s figure of Margaritana 
* Yet they state, ‘“ All the species of this genus known are from the rivers 
of South America,’ 
