460 NEW GENUS OF SHELLS. [December, 



it will complete the chain of connection between those 

 two genera. Alasmidonta corresponds with those genera 

 in the number of its cicatrices, but is separable from 

 Anodonta by its primary tooth ; from Unio by being 

 destitute of the lamelliform teeth; and from Dipsas also 

 by tlie last mentioned character, as well as by the pre- 

 sence of a primary tooth, which is wanting in that ge- 

 nus. 



This new genus I formerly proposed when describing^ 

 the above mentioned Unio undulata, under the name of 

 Monodonta; but as this term has been applied to a genus 

 of Univalves, I have substituted that oi Alasmidonta, 



Description of two new Species of Linnaean Lacerta, 

 ^ j» By Jacob Giliiams. 



Genus SALAMANDRA. 



^.Wfiriolata, Plate 18. fig. L JBodj/ black, with a 

 ylight violaceous tinge, and irregular white spots, which 

 are more numerous on the sides, and wanting on the 

 venter and inferior portion of the tail, but are present 

 beneath the lower maxilla; every part of the surface cover- 

 ed with numerous,* approximate, pale dots. JEt/es some- 

 what prominent. Teeth minute, numerous. Tail very 

 slightly compressed, gradually and regularly attenuated^ 

 acute. Posterior feet five-toed, the inner toe hardly pro- 

 minent; anterior feet four-toed, the inner one small. 



Total length three inches and four fifths; from the tip 

 of the head to the origin of the hind feet, one inch and 



