8 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 50 



its reticulate instead of spiral sculpture, its better differentiated canal, 

 and in having two instead of three columellar plaits. The type, 

 F. (G.) panamensis Dall, is figured in the Transactions of the Wag- 

 ner Institute of Science, volume in, plate xin, figure 5, 1892. 



The Volutoderma of the Aachen chalk are characterized, as above 

 noted, by a quite different type of sculpture from those of India or 

 even of Gosau, not to speak of the United States. They vary con- 

 siderably in form, as do the analogous groups in other regions, but 

 have a distinctly common facies. For these I propose the sectional 

 name Rostellaca, with R. zitteliana Holzapfel as type. 1 



The fauna also contains the following other species which I refer 

 to the same section: V. (R.) subsemiplicata Orbigny; V. (R.) 

 fenestrataR.oem.tr; V. (R.) gosseleti Holzapfel and V. (R.) holzap- 

 feli Dall, 2 the last being obviously distinct from V. fenestrata Roe- 

 mer, with which it is united in Holzapfel's monograph. 



Passing over for the moment the Greensand marls of New Jersey, 

 we may consider next the group of species described by Stanton 3 

 from the Pugnellus sandstone of Huerfano Park, Colorado, which 

 form probably the oldest assembly of this family yet described from 

 the United States. 



In this group the number of species known is not large, and none 

 of them are typical Volutoderma. The list comprises Volutoderma 

 (Rostelliiida) dalli Stanton and a varietal or possibly specific form 

 plicatula Dall 4 ; V. ambigua Stanton; V. (Rostellana ?) gracilis 

 Stanton; and V. {Rostellana?) constricta Dall, 5 the latter two 

 being nearly intermediate smooth types. 



The Greensand marls of New Jersey contain a large Volutoid 

 fauna, which, unfortunately, is preserved only in the form of in- 

 ternal casts. This forbids very satisfactory identifications specific- 

 ally. Still the impressions distinctly convey the idea that a number 

 of the shells belonged to the genus Volutoderma in the strict sense, 

 while the others, as usual, assume a variable aspect. Altogether 

 there are five or six species of Volutoderma in the lower marls and 

 four species of Volutomorpha Gabb. The latter genus differs from 

 Volutoderma by its sculpture, by having a single strong plait on the 

 columella, and especially by the fact that the outer surface in the 

 adult is covered with a varnish-like enamel. The principal character 



1 Holzapfel, Paleontographica, Bd. xxxiv, taf. vni, fig. 40-fc. 



3 Holzapfel, op. cit., taf. vni, fig. 6. 



8 Bull. No. 106, U. S. Geological Survey, 1893, pp. 155-158, pis. xxm, xxiv. 



4 Stanton, op. cit., pi. xxxiii, fig. 10. New name. 

 * Stanton, op. cit., pi. xxxiv, fig. 3. New name. 



