THE NAUTILUS. ">"' 



earlier, it is likely that Prof. Dall recognized the form after the 

 publication of the nude name in Man. Conch., but before it was 

 scantily clothed with a description in the October NAUTILUS. 



Call's first notice of the form referred merely to Binney's figures ; 

 but lately he has given an account of it which leaves nothing to be 

 desired save an equally good notice of the soft anatomy. 



NEW UNIOS. 



BY BERLIN H. WRIGHT. 



Unio Buxtoni sp. m>v. 



Shell very transverse or wide, subcylindrical, moderately and 

 uniformly inflated, subsolid, bluntly pointed and attenuated behind, 

 obliquely rounded in front and straight on the dorsura. Epidermis 

 olive-black and obscurely rayed throughout. Growth lines obscure. 

 Umbos depressed. Beaks pointed and very small, with two or three 

 distant, nodose undulations. Umbonal ridge rounded or subangular. 

 Beak cavities slight ; cavity of valves ample. Lateral teeth 

 straight, slender, thin and long, the inner one thicker and higher, 

 and both extending to the cardinals, which are erect, short, with 

 many curved ridgelets on the upper faces, double in the left and 

 single in the right valves. Cicatrices slightly impressed but well 

 defined, the anterior ones distinct, the smaller ones being crescent- 

 shaped, which divides occasionally into two separate pits; posterior 

 ones confluent and much elongated ; dorsal ones well impressed and 

 in the beak cavity. Pallial line distinct, at which the coruscations 

 end. Nacre uniform and of a brilliant copper tint. Width 2J 

 inches, length f inch, diameter v inch. 



Habitat. Lakelets of Marion Co., Florida. 



Type in National Museum. 



Remarks. Affinity, U. Waltoni B. H. Wright, and U. na.sntn/iix 

 Lea. From the former it differs in being smaller, more solid, cylin- 

 drical, darker colored, more prominent umbonal ridge, not sub- 

 emarginate at base, and in having a more prolonged dorsal line be- 

 hind. Behind, and in size and structure, it reminds one of U. nasu- 

 tiilus, which never has an upturned keel in front as in our shell, and 

 has a livid nacre. 



We have great pleasure in naming this species for our good friend 

 and naturalist, Mr. William W. Buxton, of Milo Centre, N. Y., 

 whose company has so often enlivened our collecting excursions. 



