FRESH WATER AND LAND SHELLS. 219 



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 J 'blialus of the Ohio. 



1 name it after Dr. Stewardson, to whose exertions we arc indebted for its discover)'. 



Unio Hanleyianus. PI. XXIII. Fig. 37. 



Testa lxvi,obli(jun, tumidd, valde insequilaterali, pottice* angulatd ; vaJvulit percrattit } until/its grandibus, 

 tumidis; epidermide bruneo-olivd, striata, eradiatd ; dentibut cardiualibus parvis, pyramidatis ; lateraRbus 

 brevit rtctisque; margarita alba it 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 while and iridescent. 



Hub. Coosawattce river, Murray county, Georgia. Dr. Boykin. 



My cabinet. 

 Diam. .8, Length .0, 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 obtusely 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. 



Ri marks. — Three or four specimens arc 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 scalenius, 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 dillers in being less rounded, of a lighter 

 colour, and having the marks of growth closer. 



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

 British MoUusca, &c." 



Unio placitus. PI. XXIII. Fig. 38. 



Tbotd htoi t eBifltic&,tubinflatd, insequilaterali, po lice tuban ?ulata; valvuUt tuberattitj notibut subpromi- 

 nnitHriH, rotundotii; epidermide cottoned, nitidd, rodiatd; dentibut cardinalibui tubparvit, com\ 



tit, ],rr obliquu, erenulatit) lateralibus tublon^ is, /mm-l/atis curvisquc; mnrzaritd sa/wnnis colore tinctd. 



8 II smooth, elliptical, rather inflated, inequilateral, subjugular behind; valves a little thick; beaks some- 

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

 compressed, very oblique, crenufcte; lateral teeth rather long, lamellar and curved; nam' salmon coloured. 



