26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 128 



Discussion. — Bunomeryx elegans was the second of the two species 

 described by Wortman. The principal justification given for separate 

 recognition is in the short diastema between P2 and P3. Also, Wort- 

 man stated that all the teeth in B. elegans are smaller, and particularly 

 P4, which is considerably narrower and has a less-developed internal 

 cusp. Moreover, it is stated that M^ has a better-developed hypocone. 

 Doubt may be entertained as to the validity of this species, as some 

 of the characters cited cannot be well defended. The length of the 

 diastema between P2 and P3 in B. elegans is about 2.5 mm. In a 

 Carnegie Museum specimen (No. 2951), that was referred to by 

 Peterson (1919, p. 67) and otherwise corresponds to B. elegans, there 

 is a diastema of 1.3 mm. On the other hand, a U.S.N. M. specimen 

 (No. 20394) of B. montanus, that has this portion preserved, has a 

 diastema of i.i mm., so that Wortman's "most important" difference 

 appears to be a variable character. Moreover, not all the teeth of 

 B. elegans are smaller, as M^ and probably M^ are equally as large 

 as in the type of B. montanus. The lower teeth, however, are narrower 

 and P4 is shorter, and although these dififerences are not great it is on 



MEASUREMENTS IN MILLEMETERS OF DENTITION IN TYPE SPECIMEN OF 



Bunomeryx elegans, a.m. no. 2066 



Length of upper cheek tooth series, P'-M^, inclusive 28.7a 



Length of upper molar series, M^-M^ inclusive 15.50 



P^ anteroposterior diameter : transverse diameter* 4-3 : i -7 



P^ anteroposterior diameter : transverse diameter 4-6 : 3-6 



P*, anteroposterior diameter : transverse diameter 3.7 : 4.7 



M\ anteroposterior diameter : transverse diameter* 5.0 : 5.8 



M', anteroposterior diameter : transverse diameter 5.4 : 6.8 



M', anteroposterior diameter : transverse diameter 5-4 :• • • 



Length of lower cheek tooth series, anterior margin of canine alveolus 



to posterior margin of M3 38.4^ 



Length of cheek tooth series, anterior margin of alveolus for Pi to pos- 

 terior margin of Ms 3S-So 



Length of premolar series, anterior margin of alveolus for Pi to pos- 

 terior margin of P4 i8.8a 



Length of molar series, M1-M3, inclusive 16.7 



Pa, anteroposterior diameter : greatest transverse diameter 4.6a : 1.7 



Ps, anteroposterior diameter : greatest transverse diameter 4.7 : 2.1 



P4, anteroposterior diameter : greatest transverse diameter 4.7 : 2.8 



Ml, anteroposterior diameter : transverse diameter of talonid 5.2 : 3.6 



Ma, anteroposterior diameter : transverse diameter of talonid 5-2 : 3-9 



Ms, anteroposterior diameter : transverse diameter of trigonid 6.9 : 3.5 



a. Approximate. 



* Measurements of posterior upper premolars are taken anteroposteriorly across outer por- 

 tion and transversely perpendicular to outer margin. Those of upper molars are taicen 

 anteroposteriorly perpendicular to anterior margin and transversely across anterior portion 

 of tooth. 



