1917.] NATURAL SCIENCES OF PHILADELPHIA. 289 



increasing in size; protoconch rather small, smooth and very low, 

 coiled two and a half times, initial turn minute and completely 

 immersed in the succeeding whorl, remaining nuclear turns very low 

 and broadly rounded, becoming increasingly higher toward the close 

 of the protoconch; sculpture very ornate, incremental striations very 

 numerous and well developed in interspiral depressions but obsolete 

 for the most part on the crests of the spiral fillets, axial ribbing 

 irregular in strength and occurrence, tending to develop into varices 

 at more or less regular intervals; spiral bands or fillets about fourteen 

 in number on the body, becoming low and crowded on the pillar, 

 fillets narrow, rectangular in cross-section, widely and irregularly 

 spaced; suture sharply impressed; body well rounded, constricted in 

 front into a narrow slightly curved pillar, aperture pyriform; outer 

 lip broken away; inner lip excavated at the base of the body, reflected 

 but adnate along the middle of the pillar; columella smooth, enlarged 

 at the entrance of the anterior canal; parietal wash very thin. 



Dimensions (immature individual). — Altitude 24.9 mm.; maximum 

 diameter 14.8 mm. 



This species is well characterized by its stout fusiform outline, 

 deeply impressed suture and highly ornate external surface. Only 

 two individuals are known. They were collected from Coon Creek 

 and are the first representatives of this genus to be reported from 

 the Cretaceous. It is interesting to find these shells in the American 

 Cretaceous since the genus is already well known in the American 

 Tertiary. Lirosoma cretacea resembles L. sidcosa Conrad^^, the type 

 of the genus which comes from the Chesapeake Miocene, in general 

 form, lirate ornamentation and character of the protoconch, but 

 differs widely from the Miocene species in detail of sculpture and 

 in the presence of irregular axial ribs which tend to develop into 

 varices at more or less regular intervals. The species Tortifiisus 

 curvirostra Conrad from the Miocene of North Carolina and Virginia 

 is regarded by Cossmann^" as another species of Lirosoma. 



The genus Ranularia Schumacher is another group of forms which 

 should be considered in determining the generic relations of the 

 Upper Cretaceous species described above. The French Eocene 

 form Ranularia piraster (Lamarck) which is figured and regarded 

 by Cossmann-^ as very typical of that genus, has a stout fusiform 



" Conrad, T. A., 1830, Jour. Acad. Nat. Sci. Phila., Vol. VI, 1st ser., p. 220, 

 PL IX, fig. 8; Martin, G. C, 1904, Md. Geol. Survey, Miocene, p. 183, PI. XLVII 

 fig. 1- 



20 Cossmann, M., 1901, Ess. de Pal. Comp., livr. iv, p. 79. 



21 Idem., 1903, livr. v, p. 97, PI. Ill, fig. 12. 



