388 C. R. Eadnian — On the Genus Peripristis. 



antiquvs, E. primi genius, Bhinoceros leptorJiinvs, Bos primigenivs, and 

 the molluscs Pyramidula rotundata, Pahidestrina marginalis, JJnio 

 littoralis, Corbicula fluminalis, etc., together with many Palaeolithic 

 implements.^ As this tooth presents no characters by which it 

 can be differentiated from that of Trogontherium Cuvieri, it is 

 provisionally placed in the same species. 



II. — On the Genus Pertpsistis, St. John. 



By C. E. Eastman, of Cambridge, Mass., U.S.A. 



rpHE genus Peripristis was established in 1870 by Orestes H. 

 L St. John^ for the reception of two species of Carboniferous 

 fish-remains, one of which had been previously described by 

 Newberry & Worthen under the name of CtenoptycJiiiis semicircularis,^ 

 and was selected as type of the new genus. The other was known 

 in collections and printed catalogues under Agassiz's manuscript 

 title of Pristodus falcatus, but this name did not acquire validity 

 until J. W. Davis adopted it in his monograph of 1883.* As there 

 can be no question that the two species are congeneric, it follows 

 that St. John's appellation of Peripristis has priority over Davis' 

 term, and the type species becomes P. semicircularis (N. & W.) 

 instead of P. falcatus, Davis. 



The claims of Peripristis to recognition as a distinct genus were 

 first impugned by J. S. Newberry, who, without having access to 

 the foreign material associated by St. John with P. semicircularis, 

 professed himself " unable to recognize more than specific differ- 

 ences " ^ between these teeth and those known as Ctenoptychius 

 serratus and C. dentatus. Previous to this, however, Newberry 

 had been inclined to separate the American form ft-om other species 

 of Ctenoptychius, but had refrained from so doing owing to in- 

 sufficiency of material at his command for comparison. We find 

 him writing in 1866 that " it is very apparent that the species 

 which have been referred to Ctenoptychius require separation," and 

 that the form named by him C. semicircularis differs so widely from 

 C. apicalis, Ag., as to render it " doubtful if they should even be 

 included in the same genus." ^ A few years later, after his sug- 

 gestion had been carried into effect by St. John, and without having 

 examined actual specimens of 'Pristodus,' he saw fit to retract his 

 former views, and liis procedure in cancelling St. John's genus has 

 been followed by subsequent writers. It is unfortunate that this 

 error on Newberry's part should have been perpetuated, since even 

 casual inspection shows that the types of Peripristis and ' Pristodus' 

 differ only in minor particulars, and that both are widely removed 

 from Ctenoptychius. 



1 These implements have been figui-ed and described by Mr. W. M. Newton in 

 " Man " for June, 1901, art. 66. 



2 Proc. Amer. Phil. Soc, vol. xi (1870), p. 434. 



3 Pal. Illinois, vol. ii (1866), p. 72, pi. iv, fig. 18. 



* Trans. Eoy. Dublin Soc. [2], vol. i (1883), p. 519, pi. Ixi, figs. 17-22. 

 s Kept. Geol. Surv. Ohio. vol. ii (1875), p. 52. 

 6 Pal. Illinois, vol. ii (1866), p. 73. 



