Clarke — The Naples Fauna. 87 

 Gephyroceras Holzapfeli, sp. now 



Plate VII, Fig. 17. 



This species lias the general expression of J'rohdocerax Luther i in its 

 compressed, discoidal whorls and flattened, grooved periphery. It is, however, 

 somewhat more widely umbilicated and the form of the suture is one degree 

 more simple, sufficient to exclude the species from an accurate generic 

 association with Probeloceras and showing 

 agdin the close phyletic connection of the 

 forms here termed Gephyroceras, with the 

 Beloceras series. At a stage of growth in 

 which the suture of Probel. Luther i is fully 

 matured, that of Gephyr. Holzapfeli has obtuse m „„ x tr , .„ m , , 



*> *J Figure 65. Gephyroceras Holzapfeli. The adult 



lateral saddles and sublateral lobes, pre- suture - 



senting in this respect, which is the mature condition of the species, a 

 reproduction of an immature condition in Probel. Luther/'. The sharpening 

 of these lobes and saddles is not attained by the species in any stage of 

 growth, hence upon this difference, we place it with Gephyroceras. 



But a single example of this form has been observed, a pyritized shell 

 covering slightly more than live volutions and showing septa throughout its 

 extent. Its greatest diameter is 7 mm., a size about the same as that of 

 Prob. Ljutheri at the same stage of growth. The specimen was obtained by 

 Dr. D. F. Lincoln on Eighteen-mile Creek, Erie county, near the crossing of 

 the Lake Shore railroad, and is believed to be from the lower Portage shales 

 at this place. The similarity of the species to Gon. forcipifer, Sandberger, is 

 striking, but there is a difference in the greater umbilication of the New York 

 shell, in the sharper curvature of the umbilical lobe and slight development of 

 the umbilical saddle. 



Gepiiykocekas catapi i k acti* m, sp. nov. 



Plate VI, Figs. 3-9. 



Small specimens only are known of this species, the largest not exceeding 

 10 mm. in diameter. The form presents a number of interesting characters 

 and serves, among other things, to again exemplify the rather loose construc- 

 tion that we feel compelled to place upon the genus Gephyroceras. 



This species has been found only in a calcareous concretion near Java 

 village, in which it is exceedingly abundant, but the greater part of the 

 specimens are preserved in calcite, making their extraction from the matrix a 

 matter of extreme difficulty. Fortunately a small quantity of barium sulphate 

 exists in the rock and has furnished some nice replacements, though the}' are 

 exceedingly tenuous and delicate. 



