176 J. B. Hatcher — Recent and Fossil Tapirs. 



just cited : " The comparison of a sufficient series of skulls in 

 any species of Tapir shows the existence of a very remarkable 

 extent of individual variation in minor dental and cranial char- 

 acters; and I have not found any of the differences pointed out 

 by Dr. Gill as distinguishing T. dowi from T. bairdii to be 

 constant, except the extraordinary modification of the fronto- 

 nasal region." After figuring and describing at some length 

 the different characters in the region of the nasals, on page 

 100, Alston summarizes these characters as follows : 



" 1. T. bairdii. Nasals well developed, each ossified from a single 

 center, separate throughout life, thick at their base, and 

 articulated with one another for the greater part of their 

 length." 



" 2. T. dowi. Nasals very small, each ossified from two centers, 

 thin, more or less separated from one another by an ante- 

 rior prolongation of the frontals, with which they become 

 partially or entirely ankylosed before the animal reaches 

 maturity." 



Had Alston had more material he would doubtless have 

 arrived at the same conclusion regarding the nasal characters 

 that he did in regard to those of other parts of the skull. 

 I find these characters exceedingly variable, and in the very 

 extensive collection of skulls of Elasmognathus in the National 

 Museum, which I have had the privilege of examining and fig- 

 uring, every gradation between these two types of nasals is 

 shown. I have selected a series of five of these skulls, show- 

 ing as many different degrees of variation, and have had the 

 fronto-nasal region in each drawn, and they are shown here in 

 pi. Ill, figs. A, B, C, D, E. From an examination of these 

 figures in connection with what has already been said, it will 

 at once be seen that as yet no character has been found by 

 which it is possible always to distinguish E. dowi from E. bair- 

 dii, and they might be considered synonyms, although I have 

 preferred to retain both, and consider the former as the less 

 specialized of the two, and the direct ancestor of the latter, 

 which has not as yet been fully differentiated from it. It 

 might better be considered as a sub-species. 



Phytogeny. 



Wortman* and Earle in their most excellent paper entitled 

 u Ancestors of the Tapir from the Lower Miocene of Dakota" 

 have reviewed very fully the work done by Marsh, Cope, Scott 

 and Osborn on the phylogeny of the Tapirs. They (Wortman 

 and Earle) derive the true tapirs from the Wind River genus 



* See Bull. Am. Mus. Nat. Hist., vol. v, pp. 159-180. 



