1^2 Notice of two New Fossil Mammals. 



laqiieatus, Mylodon Darwinii, and to which might be now also 

 added Orycterotherium Missouriensis. In fine, Pleurodon would 

 characterize a group of genera, but Mylodon affords no character 

 whatever. „ 



Prof. Owen has recently read a memoir before the Geological 

 Society of London, on the fossil bones contained in Mr. Kock's 

 collection now exhibiting in London, and during last autumn in 

 Philadelphia. Mr. O. after a minute examination of the numer- 

 ous portions of the mastodons in this collection, of every age and 

 size and of both sexes, many with the tasks of the inferior jaw 

 in various stages of development ; and on the existence of which 

 the late Dr. Godman attempted to construct a new genus under 

 the name of " Tetracaulodori'^ — arrives at the conclusion, that 

 all these mastodon crania belong to one species, and that the ge- 

 nus " Tetracaulodon" is without foundation. A conclusion at 

 which we arrived immediately, so soon as the name was pub- 

 lished ; our opinion was made public at the time, and again re- 

 published in the Medical and Physical Researches, p. 257. Cop- 

 ies of this notice were sent to scientific persons abroad, to editors 

 of journals, (fee, and Mr. Owen possessed a copy. The notice 

 was also republished in Jameson's Edinburgh Journal. The genus 

 '' Tetracaulodon^''^ has long since been consigned to the " tomb 

 of the Capulets." The subject, in fine, is one upon which no 

 two naturalists could contend in opinion. If a difference of opin- 

 ion had existed, the decision of Prof Owen, with such a mass 

 of material on which to found .his judgment, with the naturalists 

 of Europe, will admit of no appeal. 



In the Transactions of the American Philosophical Society for 

 1831, 1 published a notice of " Ichthyosaurian Remains discov- 

 ered in the State of Missouri." This essay was republished in 

 the "Medical and Physical Researches," 1835, p. 344. Subse- 

 quently in 1839, January 9th, I read a memoir upon the same 

 subject before the London Geological Society, and proposed to 

 change the name of this animal to " Batrachosaurus Missouri- 

 ensis." 



I was shown by Professor Goldfuss of the University of Bonn, 

 in Oct. 1839, a principal portion of the skeleton of a fossil ani- 

 mal of this kind, brought from Missouri by Maximilian Prince 

 de Wied. 



