UNITED STATES. 37 



and minutely maculate, more like hrev'ulois (nobis). In some of its cliaracters it is 

 closely allied to hrevidens. The outline is very different, but the color of the epidermis 

 is nearly the same, and the rays on the posterior portion of both are of the same 

 j)oculiar character us regards the minutely dotted rays there, while on the side and 

 on the anterior portion the rays are in both species capillary, and very little 

 interrupted. The indentation of th^ palleal cicatrix is remarkable, and 1 know of 

 but two other species whiclu have this character in the males, viz., the hrevkhm and 

 penifics Con. In the females of several other species, where the feminine character is 

 marked in the shell by a dentated margin, this indentation of the palleal cicatrix is 

 not uncommon, but I know no other species than these three where it occurs in the 

 males. The compacts in its outline is not so transverse as penitus, but it has the 

 same dotted rays, which,, although obscure in penitus, exist in all of my sjjecimens, 

 but which are not noticed by Mr. Conrad. It could not be easily confounded with 

 that species. The arch formed at the junction of the cardinal and lateral teeth is not 

 so marked as in Woodwardianus, but is still remarkable. Troschel, in Weigmann's 

 Arch., V. 13, p. 26G, says that the family Naiades is without emargination of the 

 palleal (-icatrix, but that is not the case in the two species stated above to have it. 



UiVIO FIBULOIDES. PI. 28, fig. 100. 

 Testa loevi, subrotunda, inflata, subaequilaterali ; valvulis crassis, atitice paulisper crassioribus ; natibus 

 crassis et val(16 prominentibus ; epidenuide vel fusa vel luteo-fusca, antice striata; dentibus cardiii- 

 alibus crassis, coinprcssis crenulatisque ; lateralibus curtis, crassis, rectis granulatisi|ue ; mariiarita 

 alba et iridesccnte. 



Shell smooth, nearly round, inflated, nearly equilateral ; valves thick, slightly 

 thicker before ; beaks thick and very prominent ; epidermis brown or yellowish 

 brown ; cardinal teeth thick, compressed and crenulate ; lateral teeth short, thick, 

 straight and granulate ; nacre white and iridescent. 

 Proc. Acad. Nat. Sci., 1859, p. 1.54. 



Eah. — Connasauga River, Georgia. Bishop Elliott. 



My cabinet and cabinet of Bishop Elliott. 

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



Shell smooth, nearly round, inflated, gently rounded before, nearly equilateral ; 

 substance of the shell thick, slightly thicker before ; beaks thick, swollen and very 

 prominent; ligament very short, thick and light brown ; epidermis brown or yellowish 

 brown, very minutely striate, with rather close, regular, somewhat impressed lines of 

 growth; umbonial slope raised and rounded; posterior slope depres.sed, wide, with 

 two indistinct, impressed lines on each valve, from the beaks to posterior margin ; 

 cardinal teeth thick, compressed and crenulate ; lateral teeth short, thick, granulate, 

 straight and directed towards the point of the beaks, there being between it and the 



