INSTITUTE OF SCIENCE, PHILADELPHIA. 387 



cene of the Caloosahatchie beds, Da!l ; and the Myakka River and Shell 

 Creek, VVillcox. 



Shell small, rather elevated, with a smooth, one-whorled, minute nucleus 

 and three subsequent spirally sculptured whorls; whorls shouldered by a 

 more or less evident obtuse keel above, obsolete toward the aperture ; early 

 whorls more coarsely, later ones finely evenly spirally grooved above and be- 

 low ; base amply rounded ; umbilicus very minute, margined by a stout 

 rounded striated rib ; aperture rounded, pillar broad, arched, sulcate at the 

 base opposite the umbilical rib, with a prominent pustule above and a smaller 

 one below the sulcus ; outer lip reflected and thickened in the adult, smooth 

 within, joined to the pillar by a thin callus in the adult. Alt. 4.25 ; max. 

 diam. 4.5 mm. 



The specimen from the Cape Fear River may possibly have been derived 

 from adjacent Pliocene beds. Some young specimens show a considerably 

 coarser spiral sculpture than the majority of individuals, but there are inter- 

 mediate gradations. 



Oollonia radiata 11. s. 

 Plate 19, figures 6, 7, 8. 



Pliocene marl of the Caloosahatchie; a single specimen collected by W. 

 H. Ball. 



Shell small, the (immature) type of about three whorls; the nucleus 

 small and smooth, the second whorl radiately ribbed above, and the remainder 

 of the spire smooth except for fine spiral grooving only visible under a glass; 

 periphery with a strong keel against which the suture is laid ; base strongly 

 radiately ribbed ; umbilicus small, with prominent rounded overhanging rib 

 as its boundary ; aperture (immature) rounded, with the edge modified by the 

 sculpture. Alt. 1.2; max. diam. 2.0 mm. 



This extremely elegant little shell is immature, but seems to have 

 assumed most of its adult characteristics except around the aperture. It can- 

 not be mistaken for any other species, owing to its marked peculiarities. 



Collonia chipolana n. s. 



Older Miocene of the Chipola beds, Calhoun County, Florida, Burns. 



Shell small, resembling a young specimen of C. elegantula, but with much 

 finer sculpture, rounder whorls, no tabulation at the shoulder, a less promi- 

 nent projection where the umbilical rib impinges on the aperture, and a decid- 

 edly thinner and smaller shell. There are about four whorls, which do not 

 complete the growth, as the unique specimen is immature; they are rounded, 

 with a distinct suture and finely spirally striated ; the aperture resembles in 

 a general way that of a young C. elegantula. Alt. of shell 2.2 ; max. diam. 

 2.0 mm. 



The shell, though immature, is an unmistakable Collonia, and I have 

 described it, lest it should be lost sight of, being the only representative of the 



