OF SOUTHERN INDIxi. 303 



anterior muscular impressions not confluent, lower accessory impressions opposite 

 the middle of the large impression;" type, Anodonta femlnalis, Gould, from 

 Kortli America. 



I do not know whether this form is svifficiently distinct from Anodonta, for 

 even in some of the well marked European species there is a rudiment of a tooth 

 below the heak of the left valve. 



7. Barhala* Humph., 1797. Shell moderately compressed, thin, with the 

 posterior dorsal margins generally somewhat extended wing-like, hinge with a 

 single linear tooth extending through the whole hinge margin, not interrupted below 

 the beaks, in other respects not differing from TJnio : type, B. jiUcata, Humph. 



8. Anodonta,i Cuv., 1798. Shell elongated, moderately inflated, or sub- 

 trapezoidal and then generally more compressed ; hinge without teeth, some- 

 times with a small sub-obsolete lamina under the beak of the left valve ; type, 

 A. cygnea, Linn. 



H. and A. Adams quote Symphynota, Lea, Lamproscaplia, and Patularia of 

 Swainson as sub-genera. 



9. Byssanodonta, d'Orb., 1846. Shell elongately rounded, inequilateral, thin, 

 beaks sub-anterior, moderately tumescent, hinge edentulous. H. and A. Adams 

 give a description of the anterior binge-teeth as being double in both valves and the 

 posterior rather elongated ; it would appear that the reference had been taken from 

 Unio Paranensls, Lea, but not from the true type B. Paranensis, d'Orb. 



b. Suh-family,—MYCETOPIN.¥.. 



I have already noticed the circumstances under whicb this sub-family is 

 here retained. 



10. Mycetopus, d'Orb., 1835. Shell much elongated; distinctly gaping in 

 front and somewhat less behind, sub-equilateral or inequilateral, the anterior 

 portion being the shorter one; hinge edentulous; type, M. soleniformis, d'Orb. 



10 CI. The typical species are from South America. Very few are known 

 from other countries. Hanley in lleeve's Conch. Icon., vol. xvi, refers 

 to it also Unio emaryinata, Lea, from Siam. A second allied species is from 

 Eastern Cachar rivers, Anodonta soleniformis, Benson. The shell does not differ 

 from the inequilateral forms of Mycetopus, but the animal has not as yet been 

 observed. Should it prove to resemble that of Mycetopus, what does not ap2:)ear 

 improbable on account of the strong anterior gape, it would be one more proof 

 of the admixture of a South American form in the fauna of Eastern Benoral 

 and Burma. I think d'Orbiguy's name was published in 1835, and Benson's 



♦Though I admit that, as a rule, Humphrey's names have no cLaim to priority, it does not appear to be so in this 

 case. The name was very early introduced by Deshayes, Sowerby, and others, and tlie type species which Humphrey 

 called B.plicata well known. Leach's name Dipsas, used by d'Archiac and other paliBontologists, has no jjriority 

 and was already bestowed upon a snake. 



t There is no doubt that Lamarck's name is only a coiTection of Cuvier's original Anudoniite. 



tt E 



