THE NAUTILUS. 77 



U. Texasensis Lea. Wimberly Lake, Lee Co., Texas. Allied to 

 U. parvus, U. Bealei, etc. Lea's U. Bairdianus is a synonym. 



U. Sayi Tappan. Texarkana, Texas. Allied to camptodon, but 

 easily separable from the types of that species. U. subcroceus Con. 

 seems to be the same. 



U. camptodon Say. Water works reservoir, Tyler, Texas. I do 

 not propose to go into the tremendous and involved synonymy of 

 this member of the U. parvus group. Typically the camptodon is 

 distinguished by the form of the hinge-line, which is decidedly 

 curved under the beaks. Forms very similar are found from the 

 Ohio River to East Texas and to Florida. 



U. declivis Say. Sabine River, Shelby (Jo., Texas. More angular 

 posteriorly than U. symmetricus. U. geometricus of Lea is a synonym, 

 as Lea himself ascertained, 



U. symmetricus Lea. A species allied to declivis Say, but less 

 angular. It has much the general appearance of the common 

 eastern U. complanatus. The synonymy of Hymmetrieus includes U. 

 porrectus Conrad, U. manubius Gould, and (according to Mr. 

 Simpson) U. Jamesianus Lea. Mr. Simpson kindly compared spec- 

 imens with the types of symmetricus, confirming my identification. 

 The localities are Blackfork Creek, near Tyler, Texarkana, and 

 West Yegua Creek, Lee Co., Texas. 



U. subrostratus Say var. Rutersvillensis Lea. Texarkana ; 

 Wimberly Lake, Lee Co., Texas. The extensive synonymy of this 

 species has been worked out by Prof. R. E. Call, (Bull. Washb. 

 Lab.) 



JJ. anodontoides Lea. Blackfork Creek near Tyler ; West Yegua 

 Creek, Lee Co., Texas. Exhibits no variation from the common 

 Mississippi and Ohio River types. 



Anodonta Stewartiana Lea. Neches River near Tyler. Belongs 

 to the ^4. eorp^denta group. A. virens Lea is probably a synonym, 

 and H. Linnceana Lea is closely allied. 



ON THE DISTINGUISHING CHARACTERS OF UNIO RADIATUS 

 AND UNIO LUTEOLUS. 



BY GEO, W. DEAN, KENT, OHIO. 



In the September Nautilus, Rev. W. M. Beauchamp has the 

 following queries : "Can any one point out an invariable feature 



