22 



above and below, ventricose and inflated in the middle ; umbilicus about 

 one third the diameter of the base, very deep and exposing all the inner 

 whorls up to the apex ; mouth nearly circular but narrower above and 

 very slightly emarginated or indented by the penultimate whorl : outer 

 lip apparently thin and simple, convex above and obliquely convex 

 below. Surface marked by a few narrow and not very prominent 

 spiral ridges, which are crossed obliquely by numerous flexuous 

 crenulated raised ridges or lamellae. On the outer half of the body- 

 whorl there are about seven or eight of these spiral ridges, four above, 

 and either three or four below the middle. The upper ones, one of 

 which is placed very close to the periphery, are distant and rather 

 clearly defined, but the lower ones are close together and extremely 

 indistinct. These latter, too, are exclusively confined to the outer 

 portion of the base, and disappear altogether before reaching the 

 umbilical margin.* The crenulated raised lines, however, which cross 

 the whorls obliquely, are as strongly marked in and around the 

 umbilicus as they are on the central and upper portions of the body- 

 whorl, and they are much more numerous as well as more closely 

 disposed than the spiral ridges. 



Maximum'breadth of the largest specimen collected, forty-five milli- 

 metres : height of the same, about thirty mm. 



Durham, Mr. J. Townsend : two specimens. 



This shell would probably not be regarded as a true Straparolhis by 

 those who follow the nomenclatui-e adopted by D'Orbigny, McCoy, 

 DeKoninck and Stoliczka, but it accords fairly well with the character 

 of that genus as re-defined by Professors H. A. Nicholson f and 

 James Hall. J It seems to be closely allied to and is probably con- 

 generic with the so-called Euomphalus funatus and E. rugosus of Sow- 

 erby, from the Wenlock limestone. 



Pledbotomaria perlata. Hall. 

 Pleurotomaria perlata, Hall. 1852. Pal. N. Y., Vol. II., p. 349, pi. 84, figs. 5a, b, c. 



By some inadvertence this species is figm'ed on page 341 of the 

 " Geology of Canada " for 1863, as Pleurotomaria solarioides, Hall, which 

 latter shell Prof. Whitfield believes to be a Straparolhis. 



* In figures 8a and 85 of Plate 3, the spiral ridges on the lower half of the 

 body-whorl are rather incorrectly represented. They should be less distinct, 

 closer together, and confined to the outer portion of the base. 



f Manual of Palaeontology, London. 1879. Vol. II., p. 24. 



X Palaeontology of the State of New York. 1879. Vol. V., part 2, p. 54. 



