190 DR. F J. XORTH 0> r [vol. lxxvi, 



an ancestor of SyringotTiyris ; and ' Spirifer ' randalli Simpson 

 was stated by Simpson to have a syrinx in a shell the fold and 

 sinus of which were plicated ; but in none of these cases has the 

 coexistence of the external characters mentioned, with a trans- 

 verse plate and syrinx, been proved. 



SxRUVGOTIIYRIS RAXDALLI (Simpson). 



1890. Spirifer randalli Simpson, Trans. Anier. Phil. Soc. vol. xvi, p. 441. 

 1910. Syringe/pleura randalli Schuchert, Amer. Jouvn. Sci. ser. 4, vol. xxx, 

 pp. 223-24. 



Horizon and locality of the type-specimens. — A little 

 below the Sub-Olean Conglomerate, that is, fairly high in the 

 American equivalent of the Carboniferous Limestone, at Warren, 

 Philadelphia. 



In 1910 Schuchert established a genus Syringopleura to include 

 syrinx-bearing Spiriferid shells, in which there were costa? on the 

 fold and sinus, and his genotype was Spirifer ran Jail i Simpson. 



Girty, 1 however, rejects that genus on the following grounds: — 

 8. randalli was not correctly described by Simpson, who, owing 

 to the imperfection of his material, apparently confused two forms 

 which occur together in the same formation, and he attributed to 

 the Syringothyroid species randalli the external characters of a 

 true Spirifer. Simpson described his species as being externally 

 like Sp. disjunchts, with from forty to sixty radial cost*, which 

 at once suggests that the specimen upon which that statement was 

 founded could not have been a SyringotTiyris, in which the number 

 of costse is between twenty and thirty. Girty maintains that of 

 Simpson's original specimens those which possess a transverse 

 plate and syrinx have a smooth fold and sinus. If this is the case, 

 the species is correctly regarded as a SyringotTiyris, and has a 

 smooth fold and sinus. 



Spirifer alius Hall. 



1836. Spirifer alta Hal). Proc. Am. Phil. Soc. vol. x, pp. 246-54, see also ' Pal. 



New York ' vol. h (1867) p. 248 & pi. xliii, rigs. 1-7. 

 1894. Gyrtia alta Hall & Clarke, ' Pal. New York' vol. viii, pt. 2, p. 42. 



This is a Middle Devonian form possessing a high area and a 

 transverse plate, and was regarded by Hall as a direct ancestor 

 of SyringotTiyris. There is, however, no trace of a syrinx, but 

 only a median thickening of the transverse plate, and the fold 

 and sinus are plicated. Hall compared his species with Spirifer 

 simplex Phillips, 3 Imt in that form the shell is smooth. 



1 Girty [11] pp. 548-54. 



2 J. A. Phillips, ' Figures & Descriptions of the Paheozoic Fossils of Devon, 

 Cornwall, & West Somerset ' 1841, p. 71 & pi. xxix, fig. 124. I have examined 

 several specimens of Sp. simplex from the Middle Devonian of Devon, but 

 have not obtained any evidence of the existence of a transverse plate. 



