22 THE NAUTILUS. 



Paludestrina (formerly BythineHa) aequicostata (Pilsbry). 



" " " Nicklinianavar. attenuata (Hald.). 



" " •• brevissima (Pilsbry). 



" man as Pi Is. 



Littoridina (?) monroensis (Ffld.). Described as Hydrobia. 

 Amnicoh'i sanctijohannis Pils. 

 " ftoridana Ffld. 



" johnsoni Pils. 

 Lyo gyrus Dalli P. & B. 



Gillia (?) wetherbyi (Dall). Described as Hydrobia. 

 We will be glad to hear of any other species from the State. The 

 above-named forms are all from tie St. Johns and Wekiva rivers and 

 St. Augustine, and their occurrence elsewhere will be of interest to 

 learn. Probably additional species will reward search in other 

 streams. 



They may be collected with a fine-meshed wire scoop, or by gath- 

 ering a ma-s of aquatic vegetation, drying it in the air, and then 

 shaking over a paper. This method has been very successfully prac- 

 ticed by Mr. C. E. Beecher in the Wekiva river. 



In some places Amnicolidce are incredibly numerous in lake beds. 

 The floor of Lake George, on the St. Johns, is covered in some parts 

 with mud charged with Paludestrina cequicostata , and the same spe- 

 cies has been found on the bottom of Lake Okeechobee. 



NEW SOUTHERN UNIOS. 



BY BERLIN H. WRIGHT. 



U. rotulatus, Bp. nov. 



Shell black, smooth anteriorly and over the umbos and with ele- 

 vated growth-lines over the remainder of the surface, circular, in- 

 flated, ray 1 ess ; umbonal ridge wanting, but replaced by two slightly 

 raised, diverging curved folds ; beaks retuse, blunt and broad ; sub- 

 stance of the shell l-ather thick and uniform ; beak cavity very deep r 

 wide, sharply angular and with no visible cicatrices; anterior cica- 

 trices distinct, remarkably deep and rough ; posterior cicatrices con- 

 fluent, smooth and slightly impressed ; cardinal teeth low, very much 

 notched, inclined to be double in the left and single in the right 

 valve; lateral teeth long, slightly curved, not prominent, and gradu- 



