Maryland Geological Survey 447 



? Pyropsis richardsonii t 'Whitfield, 1S92, lion. U. S. Geol. Survey, vol. xviii, 

 p. 39, pi. i, figs. 14-16. (Not P. richardsoni Tuomey, 1S55.) 



Pyropsis trachiformis f Whitfield, 1S92, Ibidem, p. 41, pi. i, figs. 4-7. 



Pyropsis trochiformis Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 23. 



Pyropsis trochiformis Weller, 1907, Geol. Survey of New Jersey. Pal., vol. 

 Iv, p. 746, pi. lxxxvii, figs. ? 1-10, 11 (ex parte). 



Description. — " Shell top-shaped ; body whorl large, inflated, covered 

 with revolving raised lines; spire depressed, not flat; angle of the body 

 whorl rounded; canal produced; aperture nearly circular." — Tuomey. 

 1854. 



Type Locality. — Xoxubee County, Mississippi. 



Shell large, an individual from Brightseat attaining a total altitude of 

 probably more than 100 mm. and a maximum diameter of 75 mm. ; spire 

 low, but not flattened : whorls five or six in number, those of the spire 

 obtusely carinated, the body whorl quite smoothly rounded in front of the 

 shoulder, but rather abruptly constricted at the base ; external surface, if 

 the shell and the cast bave not been incorrectly united, highly polished and 

 sculptured with low, broad, spiral bands separated by angular interspirals 

 of almost equal width, eleven to twelve in number on the ultima exclusive 

 of the canal, and of fortuitous secondaries; the spirals subequal, the two 

 shoulder spirals a little less prominent than those in front of them ; char- 

 acters of the canal not certainly known, but it was probably long and rather 

 broad ; aperture very wide, the outer lip thin, sharp, and semi-elliptical in 

 outline, obscurely angulated at the shoulder ; inner lip moderately exca- 

 vated at the base of the body, non-plicate. 



Pyropsis trochiformis, as used by Weller and others who were working 

 with poorly preserved material, is little more than a group name which 

 serves to include all of the larger casts of Pyropsis with rounded but not 

 globose body whorls. The degree of variation in the convexity and in the 

 sharpness of the contraction of the body is quite certainly much greater 

 than would be allowed if the shell characters w r ere preserved, but in the 

 absence of these there are no very satisfactory criteria for separation. 



P. trochiformis (Tuomey) is distinguished from P. perlata Conrad 

 not only by its less depressed spire and rounded body whorl, but also by 

 the development of a much simpler and more uniform and regular spiral 

 sculpture than that which ornaments Conrad"s species. 



