NAPLES FAUNA IN WESTERN NEW YORK, PART 2 283 



the Devonic lamellibranchiates, where a figure of a single imperfect 

 specimen was ascribed to this species, then termed Cardiomorpha 

 suborbicularis; in the final appearance of these plates accompanied 

 by descriptive text this name was altogether abandoned, and the fossil was 

 redescribed under the new designation Edmondia? tenuistriata, 

 and its geologic locality cited as the " shales of the Chemung group near 

 Elmira, N. Y." 



The following remarks were also made in justification of this change : 

 " This species has been compared with and supposed to be identical with 

 Ungulina suborbicularis, but it is entirely distinct from that form, 

 and from a different horizon." 



The specimen is, on the contrary, an excellent representative of Ung. 

 suborbicularis, differing from the original type, so far as one may 

 judge from the figure, in the presence of fine, filiform, radial striae, but this, 

 as we shall presently observe, can not be relied on as a specific character. 

 Moreover, the specimen, a piece of dark gray sandy shale, is from the 

 high layers carrying the survivors of the Portage fauna after the introduc- 

 tion of a distinct fauna from the east. 



It is the existence in varying degree of this fine radial lineation of the 

 surface that has obscured the identity of the species and seems to have 

 given birth to the name above mentioned, Edmondia? tenuistriata, 

 and also to the terms Lucina wyomingensis and L. varysburgia. 



This radial striation may manifest itself only as a few faint lines on 

 each cardinal slope close to the hinge line ; it may extend over the entire 

 cardinal slopes ; and, finally, and most often, may cover the entire surface 

 with extremely minute lines of equal size. Thus between a smooth shell 

 marked with sharp concentric lines but with no trace whatever of radial 

 striae to shells in which the entire surface is covered with fine radii, we find 

 within this species every passage stage. 



The striae along the hinge line on both sides of the beak are not 

 stouter than those elsewhere, but they slightly crenulate the margin of the 

 shell on the posterior side of the beak, as the others do not. 



