FRESH WATER AND LAND SHELLS. 35 



it really is there enlarged. The position, therefore, of the oviducts of the animal, which 

 I have not seen, must be different. Judging from this single specimen, I should think it 

 will prove to be a much smaller species than the foliaius of the Ohio. 



I name it after Dr. Stewardson, to whose exertions we are indebted for its discovery. 



Unio Hanleyianus. pi. XXIII. Fig. 37. 



Testd Ixvi, obliqud, tumidd, valde insequilaterali, postice angulata; valvulis percrassis ; natibus grandibus, 

 tumidis; epidermide bruneo-olivd, striata, eradiatd; dentibus cardbialibus parvis, pyramidalis ; laleralibua 

 brevis rectisque; margaritd alba et iridescente. 



Shell smooth, oblique, swollen, very inequilateral, angular behind; valves very thick; beaks large and 

 swollen; epidermis brownish-olive, striate, without rays; cardinal teeth small, pyramidal; lateral teeth short and 

 straight; nacre white and iridescent. 



Hab. Coosawattee river, Murray county, Georgia. Dr. Boykin. 



My cabinet. 

 Diam. .8, Length .9, Breadth 1.4 inches. 



Shell smooth, oblique, swollen, very inequivalve, angular behind; substance of the shell 

 very thick, much thinner behind ; beaks large, swollen and placed towards the anterior 

 margin; ligament short and thin; epidermis brownish-olive, striate, without rays and with 

 close marks of growth; posterior slope wide and rather depressed ; umbonial slope raised, 

 very obtu-sely angular; cardinal teeth small, pyramidal, single in the right, and double in 

 the left valve; lateral teeth short, straight and in a direction much above the cardinal 

 tooth; anterior cicatrices distinct and deeply impressed; posterior cicatrices distinct; 

 dorsal cicatrices on the under side of the plate; palleal cicatrix impressed; cavity of the 

 shell deep and irregularly oval; cavity of the shell shallow and obtusely angular; nacre 

 white and iridescent. 



Remarks. — Three or four specimens are before me, differing very little from each other. 

 The marks of growth are unusually close together, and are much darker than the inter- 

 space, which is brownish-olive. It is a pretty little species, and is allied to U. decisus^ 

 (Nobis,) and scalenlus, Raf., and approaches U. pulvinulus, (Nobis.) It differs from the first 

 in not having the beaks so terminal, and not being so much swollen on the anterior por- 

 tion of the disk; from the second, in not having the beaks so terminal, in being more 

 oval and in being without rays. From the last it differs in being less rounded, of a lighter 

 colour, and having the marks of growth closer. 



I dedicate this species to Sylvanus Hanley, Esq., one of the authors of " History of 

 British Mollusca," &c. 



Unio placitus. PI. XXIII. Fig. 38. 



Testa Imvi, elHpticd, sicbin/?atd, inisquilaterali, postice subangulatd ; valvulis siibcrassis; natibus subpromi- 

 nentibus, rntundatis; epidermide castaned, nitidd, obsolete rudiatd; dentibus cardinalibus suhparvis, compre»- 

 sis, per obliquis, crenulalis; lateralibus sublongis, lamellatis curvisque; margaritd salmonis colore tinctd. 



Shell smooth, elliptical, rather inflated, inequilateral, subangular behind; valves a little thick; beaks some- 

 what prominent, rounded ; epidermis chestnut-coloured, shining, obsoletely rayed ; cardinal tcetli rather small, 

 compressed, very oblique, crenulate ; lateral teeth rather long, lamellar and curved ; nacre salmon coloured. 



