Il8 NEW YORK STATE MUSEUM 



This is the only American shell which affords satisfactory basis for 

 comparison. 



I am here again indebted to Professor Kayser and Dr Drevermann for 

 affording facilities and suggestion for comparison with European species of 

 the early Devonic. 



S. arduennensis Schnur [_scc Schnur. Brachiopoden der Eifel ; 

 Palaeontographica. 1854. 3: 199, pi. 32, fig. 3 ; Kayser. Fauna des Haupt- 

 quarzits. 1889. p-33, pi. 2, fig. 1-4; pi. 9, fig. 3; pi. 12, fig. 5; pi. 16, 

 fig. 1-9]. 



This species with which I was at first disposed to identify the shells in 

 hand is usually of small extended form with a very regularly convex ventral 

 valve and broadly rounded plications. Though distinct in outline and con- 

 tour it often represents the aspect in external and internal surface of 

 S . c y m i n d i s . 



S . d e c h e n i Kayser [sec Kayser. Fauna d. aeltest. Devon-Ablag. 

 des Harzes. 1878. p.i6s, pi. 22, fig. i, 2]. 



This is a very large species but its smaller expressions, of which I have 

 specimens from the Kellerswald, are like S . c y m i n d i s in degree of pli- 

 cation, though here it is the second rather than the first pair of lateral 

 plications that dominates the rest. The ventral valve is uniformly convex 

 but the umbo is not strongly arched. 



S . n e r e i Barrande [as identified by Walther]. Specimens from the 

 upper Coblentzian of Marburg very like this shell in general aspect are 

 somewhat more numerously plicated but a distinctive feature lies in the 

 very long dental plates such as are present in S. lateincisus. 



Locality. Edmunds Hill. 



Spirifer cymindis var. sparsa Clarke 



Plate 30, figures 12-14 



S p i ri fe r cy m i n d i s var. s p arsa Clarke. N. Y. State Mus. Bui. 107. 1907. p. 257 



Associated with S .' c y m i n d i s and quite as abundant, is a shell dis- 

 tinguished in gross by its sparser plication. Our material here presents us 

 chiefly with a series of internal casts in which there are some differences of 

 expression, noted in particular in the following enumeration : 



1 Size. The shells are of medium size, uniformly approaching S . 

 arduennensis and S. cymindis in dimensions. Differences in size 

 and age are expressed on the internal cast by a clearer definition in the 

 younger and thinner shelled examples. 



2 Outline and contour. The marginal outline is subtriangular, the hinge 

 being long and sometimes extended at the angles, the lateral margins rather 

 directly convergent. The ventral valve is elevated at the beak, the cardinal 

 area being rather high and curved, and the median part of the shell elevated. 



