XEW UNIOXID.E OF THE L XITKD .STATE.S. 7'.> 



as it is ill the left, and the interspace between the teeth form quite an arch. I name 

 this after Dr. Showalter, to whom I am greatly indebted for many fine specimens of 

 the Molluscs from Alabama. 



Unio dolosus. pi. 9, fig. 224. 



Ti'Sta hcvi, obovata, subalata, subconipressa, ad latere planulala, postice ct antice rotundata, valdc ina!i|ui- 

 latcrali ; valvulis subteiiuibus ; natibus promiuuli.s, ad apiucs minute undulatis; epidurmide virido- 

 oliva. et obsolete radiata; dentibus cardinalibus parvis, compressis crcnulatisque ; lateralibus longis, 

 lamellatis subcurvisque ; margarita albida et purpurea paulispcr tincta et valdc iridesceute. 



Shell smooth, obovate, scarcely winged, rather compressed, flattened at the sides, 

 rounded before and behind, very inequilateral; valves rather thin; beaks a little 

 prominent and minutely undulate ; epidermis, greenish olive and obscurely rayed ; 

 cardinal teeth small, compressed and crenulated ; lateral teeth long, lamellar and 

 somewhat curved ; nacre whitish, slightly tinted with purple and very iridescent. 

 Proc. Acad. Nat. Sci. 1860, p. 307. 



Ilah. — Alabama River, at Claiborne, Ala., Judge Tait. Coosa River, E. D. Showal- 

 ter, M. D. 



My cabinet and cabinet of Dr. Showalter. 

 Diam. -8, Length 1-4, Breadth 2-3 inches. 



Shell smooth, obovate, scarcely winged, rather compressed, flattened at the sides, 

 rounded before and behind, very inequilateral ; substance of the shell thin ; beaks a 

 little prominent and minutely undulate ; ligament rather long, rather thin and light 

 brown; epidermis greenish olive and obscurely rayed, with distant marks of growth ; 

 umbonial slope rather low and rounded ; posterior slope raised, compressed, with three 

 dark lines on each valve ; cardinal teeth small, compressed, crenulate and disposed to 

 be double in both valves ; lateral teeth long, lamellar and somewhat curved ; anterior 

 cicatrices distinct, rather large, well impressed ; posterior cicatrices confluent, large, 

 very slightly impressed ; dorsal cicatrices placed in a row across the cavity of the 

 beaks; cavity of the shell shallow and wide; cavity of the beaks rather shallow and 

 angular; nacre whitish, slightly tinted with purple and very iridescent. 



Soft Parts. — Branchial uterus fully charged, and occupying the j^osterior half of the 

 outer leaves of the branchice, much as in the form o^cariosus, Say, being nearly oval, 

 and the ovisacks coming below the edges of the branchia3. Branjclua; large, nearly 

 semicircular, inner one much the larger, united the whole length of abdominal sack. 

 Palpi large, falcate, united more than half way down the posterior edges. Mantle 

 very thin, thickened on the edges and fringed below the branchial opening. Branchial 

 opening rather small, with numerous minute papilla) on the inner edges. Anal opening 

 small, with very numerous minute papilljE. Super-anal ope nirij rather long, colored 

 on the edges and united below. Color of the mass whitish. 



