THK NAUTILUS. 89 



39. Limncea ainpla Migli. Lake. 



40. Limncea catascopium Say. Lake. 



41. Physa anciUaria Say. Lake. 



42. Physa sayii Tapp. Lake. 



43. Physa heterostropha Say. Lake. 



44. Planorbis carnpanulatus Say. Lake. 



45. Planorbis trivolvis Say. Lake. 



46. Planorbis bicarinatus Say. Lake. 



47. Campeloma integer Say. Lake. 



NEW SOUTHERN UNIOS. 



BY BKRL1N II. WRIGHT. 



Unio conjugans, sp. nov. 



Shell thick, solid, inflated, inequilateral, quadrate ; dorsal margin 

 arched, posterior margin truncate and subemarginate, basal margin 

 emarginate, anterior margin uniformly rounded ; umbos rounded, 

 umbonal ridge prominent, with a marked depression in front; epi- 

 dermis dark chestnut ; tuberculate throughout, the tuberculations 

 being without apparent order of arrangement or uniformity of shape, 

 except that they expand downward and each base terminates at a 

 growth-line, and near the base of the shell they become joined into 

 two broken ridges on the anterior half of the shell ; cardinal teeth 

 very heavy and deeply serrated, those in the left valve being tripar- 

 tite and those in the right valve double ; lateral teeth, which extend 

 to the abrupt posterior dorsal angle, are solid, depressed, curved and 

 comparatively smooth ; anterior cicatrices deep, contracted and 

 barely distinct ; posterior cicatrices well impressed and widely sepa- 

 rated ; pallial line deeply impressed and the pallial margin much 

 thickened in the anterior portion ; dorsal cicatrices many, small, and 

 arranged in a long oblique row under the cardinal teeth ; beak cavity 

 deep, wide and bluntly terminated ; nacre dead white with large 

 umbraceous spots. Width 3f , length 2J, diain. 2 inches. 



Habitat : Hiawassa river, Polk Co., Tenn. 



Type in National Museum. 



Remarks : Affinity, U. blandianus Lea and U. tuberculatus Barnes. 

 This species fills the gap between these species, and removes the 

 latter from the isolated position it has heretofore held, uniting the 



