INSTITUTE OF SCIENCE, PHILADELPHIA. 75 



sharp, slightly reflected, lirate within, hardly thickened; the whorls are slightly 

 turrited, usually coronated with angles or pointed spines at the shoulder, with 

 a sinus or inflection of the lip near the suture and a thin callus on the inner 

 lip, often continued over the whorl above the line of the suture, as in Harpa. 

 Under certain conditions this callus may become hypertrophied, and the 

 whorls, being continued over it, become somewhat irregular and, as it were, de- 

 formed. Specimens of V. petrosa Conrad, thus distorted, were very naturally 

 referred by him to AiJileta under the name of A. Tuomeyi. 



In the American Eocene the following species of this group are known : 

 V. petrosa Conrad (+ impressa Conr. + dnrnosa Conr. + symmetrica Conr. 

 + indenta Conr.), V. Sayana Conrad, V. rngata Conrad and V. {A'litra) Hale- 

 ana Whitfield. In Europe, F" spinosa Lamarck, V. luctator and V. am- 

 bigua Sowerby may serve as examples. V. californiana Conrad, turned out 

 to be a distorted Comts, and as there was already a d?«z<.y so named, it received 

 the name of C. Rcmondi from Gabb. 



Subgenus Volutocorbis Dall. 



Shell resembling VolntilWies, but more slender and without a coronated 

 shoulder; the sculpture is reticulate and nodose or prickly at the intersections; 

 the sutural sinus is less evident than in Volutilithes, and the suture is some- 

 times channelled. 

 Type V. ( Volutilithes) timopsis Conrad. Lower Eocene of Alabama. 



In Europe V. lima Sowerby and V. digitalina Lamarck will serve as 

 examples, in the recent fauna V. abyssicola Ad. & Rve. 



There are a few species like V. bidbida and V. labrella Lamarck which are 

 smooth or have merely a carina on the shoulder, and when adult would appear 

 to be out of place in either this or the preceding group. But an examination 

 of the early whorls will show that they really belong to Vohitilithes proper, of 

 which they are merely aberrant specific forms. 



Subgenus Athleta Conrad, 1S53. 

 Type A. rarispina Lamarck, Miocene of Europe. 



This is a short-lived type, exhibiting but one or two species. It is fore- 

 shadowed by the distorted specimens of VolutUithes petrosa to which I have 

 already referred, and which occur from the lower Eocene of Alabama (Wood's 

 Bluff) up to the Claiborne sands and the beds known as Jackson, overlying the 

 Claiborne, associated with the undistorted normal form, which is always more 

 numerous. In America, however, the deposition of callus never became nor- 

 mal and regular, though in Europe A. rarispina and A.ficulina Lam. exhibit 

 a normal, Cassis-YxV^ expansion around the aperture of what, without it, is a 

 typical Volutilithes. The establishment of the European forms took place in 

 the Miocene, which period they did not survive. The subgenus forms a short 

 side-branch from the typical Vohitilithes stem, which, apparently, started as a 

 pathologic variety in the American Eocene. 



