THK NAUTIM'S. 29 



I 



PLEUROCEIilDiE. 



Goniobasis virginica Gmel. Shells badly eroded in the Lehigh 

 River, but perfect and large among rocks at the mouth of Monocasy 

 Creek. 



SpHyERIIDiE. 



Sphcsrium simile Say. Mouth of Monocasy Creek, common. 

 Sphcerinm striatinum Lam. Saucon Creek (W. L. King). 

 Pisidium virqinicum Gmel. Lehigh River, Delaware River 

 (King). 



Pisidium eompressum Prime. Lehigh River. 



Unionid^. 

 TJnio complanatus Sol. Lehigh and Delaware Rivers, common. 

 Unio och7-aceus Say. Delaware River, common. 

 Margaritana marginata Say. Delaware River, common. 

 Anodonta Jluviaiilis Lea. Lehigh Canal; also ponds in the vicinity 

 of Bethlehem. 



NEW FLORIDA UNIO. 



BY L. S. FRIERSON. 



No very clear idea of the Unio coruscus could exist because it 

 has never been figured. Through the courtesy of Mr. Van Name, 

 of the State Museum of New York, an accurate photograph of the 

 type shell is herewith given to readers of the Nautilus (Plate I, 

 figs. 1, 2, 3). 



Mr. Van Name having also kindly compared suites of F'lorida 

 Uniones with Gould's shells (three in number), an uiidescribed shell 

 has been found which is herewith described. 



Unio tenuisculus n. sp. Plate I, figs. 4, 5, 6. 



Shell transversely elliptical, rather solid, quite small, being the 

 smallest member of the great buckleyi group yet published ; smooth, 

 eradiate (except when quite young), brown-olive, shining on the 

 sides, the posterior area rough and dull ; dorsal and basal margins 

 nearly parallel (the former a little arched in some examples). Pos- 

 terior point low and widely biangulate ; truncate in front. Nacre 

 purple and salmon-colored. Teeth double in left, single in right 

 valve, quite stout. Length 30^. alt. 20, ai.un. 14^ mm. 



