THE NAUTILUS. 



67 



\'<ilrt<i v irons Try on. Willow Creek, tributary to Susan River, 

 Lassen Co. 



Anodonta culifornieiifis Leti. Upper waters of Willow Creek. 



Marguritana margaritifera (L.). Sacramento R. at Redding. 



Pisidium utiramontanum Prime. Duck Lake, Lassen Co.; W. 

 Fork Feather R. at Morgan Spr., Plumas Co. Another species of 

 Pisidium occurred in Mocloc and Siskiyou counties. 



A NEW PLIOCENE POLYGYKA FROM FLORIDA. 



BY CHAS. W. JOHNSON. 



Polygyra caloosaensis, n. sp. 



Whorls six, slightly depressed, crossed on the body whorl above 



by about 65 coarse, oblique, subarcuate costae, that end rather ab- 

 ruptly at the periphery; toward 

 the apex they become gradually 

 smaller or obsolete, apical whorl 

 smooth ; below the periphery 

 the cost* become obsolete and 

 the surface has an indented or 

 malleated appearance. Umbili- 

 cus wide, one entire whorl (be- 

 side the body whorl) being visible 

 below. Aperture sublunate, nar- 

 rowed above, lip broad, unevenly 

 reflected, slightly thickened on 

 the base, giving the appearance 

 of an obsolete tooth, callus con- 

 tinuous over the parietal wall 

 and bearing a prominent oblique 

 process, that is subtruncate 

 above, but extends narrowly 

 toward the base. Alt. 6 mm., 

 greatest diam. 11 mm. 

 Two specimens, (one immature) from the material collected by the 



late Dr. H. G. Griffith from the Pliocene beds of the Caloosahatchie 

 River, Florida. 



