FRESHWATER AND LAND SHELLS. 57 



by Dr Griffith. Also examined a JJ, radiatus, with enlarged oviducts, 

 but not sufficiently advanced to observe any ova with a common micro- 

 scope. Several others examined proved to be males. 



June 5, 1836. — Opened an obtuse U. ochraceus, with large and full 

 oviducts. The ova only so far progressed as to be visible with the mi- 

 croscope. 



Unio spinosus. Plate XVI. fig. 50. 



Testa spinosa, subtriangulari, injlatd, inaquilaterali, postich acuto-angulata ; valvuUs 

 subcrassibus ; clivo umboniali carinato ; natibus vix prominentibus ; epidermide atro-fusca^ 

 glabra; dentibus cardinalibus deorsum incUnantibus ; later alibus subgrandibus subcurvisque ; 

 margarita purpurea. 



Shell spinous, subtriangular, inflated, inequilateral, acutely angular behind ; valves 

 rather thick; umbonial slope carinate ; beaks scarcely prominent; epidermis dark brown, 

 shining; cardinal teeth inclining downwards ; lateral teeth rather large and curved ; 

 nacre purple. 



Hab. Altamaha, Hopeton, near Darien, Geo. James Hamilton 

 Cowper, Esq. 



Hab. Altamaha, Liberty County, Geo. Lewis Leconte, Esq. 



My Cabinet. 



Cabinet of Professor Shepard. 



Cabinet of Professor RaveneL 



Cabinet of Major Leconte. 



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



From tip to tip of fourth pair of spines, 2-6 inches. 



Shell spinous, subtriangular, inflated, inequilateral, acutely angular 

 behind ; arcuate on the dorsal margin ; substance of the shell rather 

 thick, thinner behind ; spines erect, opposed in each valve, placed in a 

 row before the umbonial slope and nearly parallel thereto ; umbonial 

 slope carinate; beaks scarcely prominent; ligament short and thick; 

 epidermis dark brown, shining, finely wrinkled ; cardinal teeth in- 



VI. — P 



