REPORT OF THE STATE PALEONTOLOGIST I903 2$ I 



is no difficult}^ of determination. The larger size and angular cardi- 

 nal extremities of S . m it r c h i s o n i are readily distinguished 

 from the smaller size and usually rounded cardinal extremities of 

 S.cyclopterus. 



S. murchisoni is abundantly represented in the Port Ewen,^ 

 Lower and Upper Oriskany. 



Summary of the preceding discussion of the Spirifers 



S . V a n u X e m i may possibly, as far as external characteristics 

 are concerned, have been derived indirectly from the western species 

 of S . c r i s p u s (or both from S . p e t i 1 u s ) and has probably 

 given rise to S.cyclopterus. 



The young of S. cyclopterus could hardly have become 

 modified into S . c o n c i n n u s though they are exceedingly 

 similar, for the finer plications of S. concinnus are present 

 even on the youngest shell examined. 



S. cyclopterus may probably have given rise to S . mur- 

 chisoni for though the young of all the latter examined have a 

 less incurving of the pedicle valve than the former, yet there is an 

 indication of a slightly increased incurving in the younger shells over 

 the older ones. In all other respects the young are apparently simi- 

 lar. Hall and Clarke indicate a close relationship between the above 

 species.2 They place them all under the S . c r i s p u s type. 



S. arenosus (Conrad) 



One specimen from the Upper Oriskany, a mere fragment of a 

 pedicle valve, is doubtfully referred to this species. 



S. macropleura (Conrad) 



Exceedingly abundant in the Lower New Scotland and also in 

 the lower part of the Upper New Scotland. It is found more usually 



'The Port Ewen specimens are more or less transitional. They are like 

 S. murchisoni in having angular plications and a subangular sinus. 

 They are similar to S. cyclopterus in being usually small and having 

 rounded cardinal extremities. The convexity of the pedicle valve is inter- 

 mediate between the two species. 



^Pal. N. Y. V.8, pt2, p.19, 36. 



