8 AMERICAN PERMIAN VERTEBRATES 



bifid tubercle. In the implantation of the teeth and their successional develop- 

 ment, these reptiles resemble the Mosasaurs. 



These characters, with others mentioned below, indicate two distinct 

 families, which may be called the Nothodontidae and Sphenacodontidae, from 

 the typical genera here described. 



Tliis paper by Marsh, of which the foregoing is the introductory 

 part, was actually published on May 3, 1878, five days prior to 

 the publication by Cope of his paper on the Texas fauna contain- 

 ing the description of numerous new forms, and in which was pro- 

 posed the family Clepsydropidae and the suborder Pelycosauria, a 

 preliminary notice of which was published in the American 

 Naturalist for May, 1878, distributed (fide Cope) on April 22, giving 

 priority to several of the generic names which later appeared in 

 his Paleontological Bulletin, No. 29. The further history of the 

 publication of these papers makes one of the most regrettable 

 pages in the scientific and personal controversy between these 

 two eminent men and need not be given here. Those who are 

 curious may find further details concerning it in a paper published 

 by Cope the following month in the American Naturalist (June, 

 1878). Suffice it here to say that the names proposed by Marsh in 

 his paper have an actual priority of five days in publication over 

 those of Professor Cope, as distributed in his Paleontological Bul- 

 letin, No. 29, and over all the names applied to the Texas Permian 

 vertebrates save that of Eryops, purporting to have been published 

 the preceding November, and those published without description 

 by Cope in the American Naturalist, for May, 1878, as follows: 



Diadectes, Bolosaurus, Epicordylus, Empedocles, Parioxys, Tri- 

 merorhachis, and Rhachitomiis . 



Under the strict rules of priority, as formulated by the Inter- 

 national Committee on Nomenclature, even these names cannot 

 claim priority over those ot Marsh, since they were merely nomina 

 nuda. If, however, any student would deny priority to them 

 after reading the paper by Cope in the June number of the Natural- 

 ist, he may; but I shall not. 



All of Marsh's types came from a bone-bed. Very few of the 

 bones were in anatomical relation, and numerous individuals of 

 six or seven forms are represented among them. I designate the 

 bed as the Baldwin bone-bed, in the descriptions. 



