1869.] Prof. Owen on Remains of a large extinct Lama. 405 



IT. "On Remains of a large extinct Lama {Palauchenia magnat 

 Owen) from Quaternary deposits in the Valley of Mexico." By 

 Professor Owen, F.R.S. &c. Received March 22, 1869. 



(Abstract.) 



The author premises to his descriptions of these remains a summary of 

 the evidence of Fossil Cameloid Quadrupeds in the memoirs and works of 

 Lund, Pictet, De Blainville, Gervais, Burmeister, and Leidy, deferring the 

 further analysis and comparison of the descriptions by the latter palae- 

 ontologist to the conclusion of the present paper. The subject of it con- 

 sists of casts and photographs of fossils discovered by Don Antonio del 

 Castillo, mining engineer, in a posttertiary deposit beneath volcanic tufa in 

 the Valley of Mexico. 



The fossils include the dentition of the left ramus of the lower jaw, 

 wanting the incisors ; also the series of cervical vertebrae* wanting the first 

 or atlas. 



Assuming the incisors to be in number as in Ruminants, the dentition 

 of this mandibular ramus is formularized as : — z'3, el, p 3, m 3 = 10. 



Of the grinding-teeth, the three molars, with the last two premolars* 

 form a close-set or continuous series of five teeth, the first of which (p 3) 

 is small, simple, conical, and obtusely pointed. A still smaller or rudi^- 

 mental premolar (p 2 or p 1) is situated in the long diastema between the 

 series of five teeth and the canine ; the latter tooth is relatively smaller 

 than in the Camel. 



Detailed descriptions are given, illustrated by drawings, of each of the 

 teeth, from which the author shows that they have belonged to a Cameloid 

 species, as large as the larger variety of existing Dromedary, but with 

 modifications of the teeth, testifying to a closer affinity with the Lama and 

 Vicugna. 



He then proceeds to give detailed descriptions, with figures* of the 

 cervical vertebrae ; they present the intraneural position of the vertebro- 

 arterial canals characteristic of the Camelidce, and of the extinct Perisso- 

 dactyle genus Macrauchenia ; and the comparisons of the fossil vertebras 

 are made with the corresponding one of that extinct genus and of the 

 existing species of Camelus and Auchenia. 



The result of the comparison concurs with that of the dental characters 

 in demonstrating the former existence in America of a Cameline Ruminant 

 as large as the largest variety of living Camel or Dromedary, with closer 

 affinities to the Lamas and Vicugnas, yet with such departures from the 

 dental and osteological characters of Auchenia, Ulig., as justify the author 

 in indicating them by the generic or subgeneric term Palauchenia, which 

 he proposes for such extinct form of American Cameline quadruped. 



The author, in conclusion, refers more at large to Prof. Leidy' s descrip- 

 tions of Procamelus occidentatis, Leidy, and Camelops Kansanus, Leidy, 

 pointing out the more important particulars wherein they differ from Palau- 



VOL. XVII. 2 H 



