56 PALEONTOLOGY OF NEW l'ORK. 



young shells the volutions are closely coiled, as shown in figure 2 of plate 15. 

 In the casts of older specimens the apex is decollated and the termination 

 smoothly rounded, as if separated hy a septum, no evidence of a continuation 

 above being perceptible. Figures 3, 4 and 5, of plate 15, represent this feature. 

 The interior volutions being rounded, the angularity on the upper side is 

 scarcely perceptible before the end of the second volution, and that of the 

 lower side about the same time or a little later. In some of the casts of the 

 interior there is a low, undefined angularity upon the back of the shell, as 

 shown in fig. 6 of plate 15. 



This species appears to be very nearly identical with Euomphalus Wahlen- 

 bergii of Goldfuss (Petrefacta, vol. 3, page 82, plate 189, figs. 7 a, b), from the 

 Eifel. That species also presents the same features in the decollation of the 

 earlier volutions, and the rounded apicial extremity, as shown in figures 3, 4 

 and 5 of plate 15. The European form is associated with E. planorbis, a species 

 much resembling E. clymenioides, which occurs in the same beds with E. Decewi 

 in western localities, and with other forms similar to those of New York. 



The specimens of this species retaining the shell, figured in the Geological Sur- 

 vey of Ohio (Vol. I, plates 19 and 20), reveal characters of the surface not shown 

 in the New York and Canadian specimens. A single remarkable specimen, 

 communicated by Dr. C. Rominger, preserves still other features not illus- 

 trated in the Ohio specimens. (See plate 27 and supplementary notice of 

 the species.) 



Formation and localities. In limestone of the Upper Helderberg group, at 

 Stafford, Batavia, and other places in Western New York ; a single speci- 

 men of the species has been found at Schoharie. It is of common occurrence 

 in the same limestone near Cayuga, Ontario. 



Euompiialus Tioga. 



PLATS xv, kk;s. ft, io, and plate xxvii. 

 Euinnphalu* Tioga, Mau.. Illustrations of Devonian Fossils : Gasteropoda, pi. 15. 1876. 



Siiei.i. discoid; upper side moderately concave from the dorso-lateral angle; 

 lower side broadly umhilicate, the dorso-basal margin acutely angular. 



