BUFFALO SOCIETY OF NATURAL SCIENCES 99 



the siphon at first may have had no expression in the shell. 

 As, however, the siphon became more prominent, there would 

 be a gradual change in the mature shell at the periphery. This 

 change would at first be slight, would become more pronounced 

 with the increased size of the siphon. 



The shallow sinus which is visible only in the adult of 

 Hercynell-i patelliformis is present even in the young of the 

 Bohemian forms, though in the very earliest part of the shells 

 of the latter the growth lines show a regular curvature with no 

 sinus. (Fig. 2.) It would seem, then, as though this species 

 from the Bertie horizon represented the ancestral condition of 

 the Hercynellas before they had acquired the pronounced radial 

 depression. I do not mean that the forms which lived in the 

 Bertie time were the direct ancestors of the forms living in 

 Bohemia in the upper Siluric and lower Devonic time, but rather 

 that the ancestors of the Bohemian forms which, to be sure, have 

 not yet been found, must have been quite similar to those which 

 are found in the Bertie, and that if Hercynellas were found in 

 this country in a higher horizon, they would probably resemble 

 the Bohemian forms to the extent of having such a pronounced 

 radial depression with consequent marginal sinus. In fact, the 

 one other Hercynella from this country, H. canadensis Grabau 

 does show just the features which would be expected. (Grabau 

 and Sherzer, Monroe formation of southern Michigan, pi. xxv, 

 figs. 5, 6.) 



Along the gentle slope of the longer axis may be seen a 

 number of slight concentric undulations, five or six being clearly 

 traceable half way around the shell. These are evenly spaced, 

 four occuring within a distance of 5 mm. They apper most like 

 the concentric undulations so marked in H. bohemica, but are 

 much fainter and more difficult to trace. Of radial striae there is 

 not the slightest indication. 



Horizon and Locality : — Associated with the preceding in 

 the Bertie Waterlime of North Buffalo. Two specimens. Types 

 in the collection of the Buffalo Society of Natural Sciences. 



Relation of the Hercynellas from the Bertie to those of 

 other Horizons. 



The species which have just been described are placed under 

 the genus Hercynella because they more closely resemble the 



