E. L. Troxell—Helaletes Redefined. 369 



over the orbits, the position of the orbits far forward, 

 the location of the antorbital foramen over P 4 , the great 

 length of the nasal bones, the narrowness of the mamil- 

 laries over the premolars, and the extent of the facial 

 vacuity already mentioned. 



Before the separate pieces were removed from the 

 original crushed skull, a cast was taken of the whole; 

 likewise a chart was made, and on both, as a double pre- 

 caution, the pieces were marked by numbers correspond- 

 ing to those on the skull itself. With this provision 

 against confusing the separated parts, the skull was then 

 almost completely dismembered; the small fragments 

 were lifted from their abnormal position and restored to 

 their right places by fitting the broken edges together. In 

 most instances the original contact was found, in a few 

 cases the matching is conjectural and only approximately 

 correct, but, considering the number of parts preserved, 

 i.e., the incompleteness of the skull, the results of the 

 operation are quite satisfactory. 



The elongated nasals are distinctly unlike those of the 

 modern tapir, but the facial depression 3 may well have 

 been the beginning of the receding nasal aperture in the 

 tapirs and seems to link more closely these two races. 

 In addition to the (1) large facial depression, one should 

 note these features which are distinctly tapiroid: (2) the 

 rising sagittal crest and the depression in the forehead, 

 which seems to be clearly indicated by the curvature of 

 the bones involved; (3) the position of the infra-orbital 

 foramen over the fourth premolar and near the orbit ; 

 (4) the very narrow maxillary above the premolars ; and 

 especially (5) the form of the teeth. The skull of the 

 young tapir lends itself particularly well to the gen- 

 eral comparison, perhaps because it is more primitive 

 than the adult and assumes more nearly the char- 

 acters of the ancestor of its race. On a young tapir 

 skull one can see the smooth upper edge of the maxillary 

 bone sending a narrow projection backward and upward, 



3 Its meaning is discussed in connection with the horses by W. X. Gregory 

 (Bull. Amer. Mus. Nat. Hist., vol. 42, pp. 265-283), who concludes in his 

 recent paper "that the lachrymal fossa of extinct Equidas did not lodge a 

 sebaceous gland like the 'larmier' of the deer and antelopes," but "prob- 

 ably did lodge a greatly enlarged nasal diverticulum" as suggested by 

 Osborn, or that the malar fossa (immediately above the premolars like that 

 of the present Helaletes) probably marks the origin of the muscle which 

 raises the upper lip. 



