240 I'liOCEEDlNGH OF THE NATIONAL MUSEUM. vol. 52. 



and differs from that of Pteraspis * in lacking a posterior median 

 spine. So far as at present known, the genus is monotypic, and 

 hmited to the Salina beds (Cayugan or "Neontaric") of the New York 

 State geological survey scheme of classification. Dr. O. P. Hay is in 

 error in citing this genus as occuring in the Onondaga stage of the 

 Devonian. 



C. DEVONIAN SYSTEM. 



Family ASTEROLEPIDAE Traquair. 



Genus BOTHRIOLEPIS Eichwald. 



BOTHRIOLEPIS COLORADENSIS Eastman. 



Bolhriolepis coloradensis Eastman, Amer. Jourii. Sci., vol. 18, 1904, p. 254, text 

 figs. 2, 4. 



The type material upon whicli this, the largest known American 

 species of the genus, was founded, is now preserved in the collection 

 of the National Museum. It was collected, together with a quantity 

 of other Devonian fish-remains, by Dr. Whitman Cross in 1903, from 

 the Elbert formation of Rockwood and Devon Point in southwestern 

 Colorado. The occurrence is interesting on account of demonstrating 

 the widespread distribution of the genus in Upper Devonian time, 

 and also because it is difficult to trace a route of migi-ation which 

 would connect this sj)ecies with its nearest ally in the western hemis- 

 ])here, B. canadensis Whiteavcs, from Scaumenac Bay in the Province 

 of Quebec, Canada. 



BOTHRIOLEPIS NITIDA (Leidy). 



Stenacanthus niliduH Leidy, Proc. Acad. Nat. Sci., Phila., vol. 8, 1856, p. 11, and 



Journal, ser. 2, vol. 3, p. 164, pi. 16, figs. 7, 8. 

 Holonerna rugosa Cope (errore), Proc. U. S. Nat. Mus., vol. 14, 1891, p. 456, pi. 30, 



fig. 7. 



This species, known only by fragmentary portions of the dermal 

 armor and appendages, occurs abundantly in the Catskill sandstone 

 along the border line between New York and Pennsylvania,. Numer- 

 ous specimens belonging to this form are contained in the Sherwood 

 and Lacoe collections, now the property of the United States National 

 Museum. One specimen in the Lacoe collection calls for special 

 notice, for the reason that it was figured and described by Cope as a 

 pectoral limb of the genus Holonerna. It is from the Catskill of 

 Mansfield, Tioga County, Pennsylvania, and bears the catalogue 

 number 1981. H. S. Williams, in 1893, first recognized it as an appen- 

 dage of Bolhriolepis, but erroneously referred it to B. canadensis. 



1 Important new light on the structure of tliis genus is contained in a paper by F. Drevermaim, Ueber 

 Pteraspis dunensis, published in Zeitschr. Deutsch. Geol. Gesell., vol. 56, 1904, pp. 275-289. It is noticed 

 by Gaskell in his Origin of the ^'ertebrates, London, 1908. See also the following by Johaim Kiaer: A new 

 Downtonian fauna in the sandstone series of the Kristiania area. Vid.-Selsk. Skrifter, Kristiania, 1911, 

 No. 7, pp. 5-22. 



