Victorian Fossils, Part XIX. 97 



is longer and more apically arcuate. It was found in the Upper 

 Helderberg (Lower Devonian) of New York State. 



Occurrence. — Silurian (Yeringian). In dai'k limestone, Loyola, 

 near Mansfield. Collected and presented by Mr. G. Sweet, F.G.S. 



Genus Platyceras, Conrad. 



Platyceras minutiim, sp. nov. (Plate V., Fig. 41 ; Plate VI., 



Figs. 57, 58). 



Description. — Shell minute, consisting of a coiled series of about 

 three whorls. Body whorl rapidly widening. Shell depressed 

 above, gently convex below. Back compressed but rounded. Sur- 

 face of whorls ornamented with distinct, somewhat salient folds, 

 curving sharply backwards, the interspaces with striated growth- 

 lines. Aperture subangulate, ovoid. 



Di7nensions. — Greatest diameter of holotype, 4.25 mm. Thick- 

 ness of paratype, 1.5 mm. 



Observations. — This extremely small species resembles the initial 

 portion of a variety of Platyceras cornntxim, Hisinger sp.,i a 

 common Upper Silurian species in Europe. In the holotype the 

 superior face shows the spire to be slightly sunken and evolute. In 

 the paratype, on the inferior face, the spire is involute. 



Occurrence. — Silurian (Yeringian). In dark blue limestone. 

 Deep Creek, a tributary of the Thomson River, Gippsland. Col- 

 lected and presented by the Rev. A. W. Cresswell, M.A. 



Platyceras cornutum, Hisinger. (Plate V., Fig. 42). 



Observations. — It is practically impossible to specifically separate 

 the many variations of this Silurian type of Platyceras, a form 

 which, by the way, also probably extends into the Devonian. It is 

 known from Great Britain, Scandinavia, Germany and the United 

 States. The synonymy is large, and for this Lindstrom's paper on 

 the Silurian Gasteropoda and Pteropoda of Gotland may be con- 

 sulted. 2 



The Victorian specimens are of the typical, intermediate form, 

 which is a neritoid shell having a depressed spire. The aperture 

 is broadly ovate, and the groAvth-lines on the shell well-marked, 

 appearing as irregular concentric folds. 



1 Pileopsia cornuta. Lethaea Suecica, 1837, p. 41, pi. xii., fig. 11. Platyceras cornutum, His. 

 ap. Lindstrbm, Sil. Gaster. and Pter. of Gotland. Kongl. Sveiiska Vet.-Akad. Haiidl., Bd. xix., 

 No. 6, 1884, p. 63, pi. ii., flgs. 29-51 ; pi. iii, figs. 6-9, 19-26. 8 



2 Tom. supra cit.. p. 63. 



