114 PROCEEDINGS OF THE ACADEMY OF [1888. 



mental area narrow, umbonial slope subangular, anterior margin 

 projecting and uniformly roimded, basal margin slightly and uni- 

 formly curved. Epidermis reddish, interrupted by coarse, distant 

 radiating lines of a blackish color. Greatest length near the 

 middle of the shell, beaks eroded and ornamented Avith three to 

 five radiating elevations. Umbos broad and rounded: nacre delicate 

 flesh color to pink, usually clear, rarely mottled with waxy spots ; 

 cardinal teeth disposed to be double in both valves, slender, ob- 

 lique, long and delicately crenulate, lateral teeth long and heavy, 

 curved; cavity of the beak deep and rounded, cavity of the shell 

 deep, and occasionally the surface is interrupted with undulating 

 ridges near the anterior portion of the cavity; dorsal cicatrices 

 forming a continuous line extending from the base of the ])osterior 

 cardinal tooth backward for one half inch and directly under 

 the edge of the roof to the beak cavity; anterior cicatrices small, 

 the superior one undermining the anterior portion of the cardinal 

 tooth, posterior cicatrices confluent. 

 Diameter 1^. Length 2.50. Breadth 4] inches. 



Habitat. Lake Woodruff^ Volusia Co. Florida. 



Mus. Acad. Nat. Sciences. Newcomb Coll., Cornell L^niv. Na- 

 tional Museum. 



Remarks. This is the largest Unio yet found in Florida waters. 

 Its place is between JJ. Savamiahensis Lea and U. Mechlenhurgensis 

 Lea. It is more inflated than the former, thinner, has more promi- 

 nent and narrower beaks, higher and more rounded umbos, deeper 

 and smaller anterior cicatrices and the teeth are lighter. 



We are pleased to name this species after our botanical friend 

 Mr. Buchard Webster of Lake Helen, Florida, who, with his father, 

 often made our collecting trips more pleasant. 



TJnio Waltoni. Plate II, fig. '.>,. 



Shell compressed on the posterior slope, transversely elongated, 

 very inequilateral; valves rather tliin, beaks not prominent and 

 eroded ; epidermis brownish black, apparently rayless, valves ante- 

 riorly rounded and oblique upward and sharply angled above, obtusely 

 rounded behind ; cardinal teeth nodulous, small, complex and serra- 

 ted; lateral teeth lamellar and slightly curved upwards; nacre purple. 

 Basal margin very nuich excurvated. 



Diameter 1.00. Length 1.50. Breadth 4 inches. 



Habitat. Lake Woodruff, Volusia Co., Florida, 



Mus. Acad. Nat. Sci. Newcomb Coll. Nat. Mus. 



