EDENTATA OF THE SANTA CRUZ BEDS. 



213 



HAPALOPS AGUIRREI (Mercerat). 



Tapinotherium aguirrei Mercerat; Rev. del Mus. de La Plata, T. II, 



1891, p. 17. 

 Hyperlepttis sectus Amegh., in part; 6num. synopt. d. Mamm. Foss. de 



Patagonie, 1894, p. 152. 

 Eucholceops ingens Lydekker, in part; Anales del Mus. de La Plata, T. 



Ill, 1894, PI. LIX, fig. 2. 



The type specimen, a skull without mandible, which is in the collection 

 of the La Plata Museum, is unfortunately much injured by crushing, which 

 greatly obscures some of the more important diagnostic features. The 

 species is of the type of H. robustus, to which it may prove to be refer- 

 able, but it displays some peculiarities and certain suggestive approxi- 

 mations to Encholceops, so that, for the present at least, it is advisable to 

 keep it distinct. The specimen has already 

 been figured by Lydekker ('94, PI. LIX, fig. 2), 

 under the name E. ingens. H. aguirrei is one 

 of the largest species of the genus, but in pro- 

 portion to the size of the skull the teeth are 

 strikingly small. The first upper tooth has the 

 usual laterally compressed, oval section and is 

 set much externally to the line of the other 

 teeth, almost as much as in Eucholceops, and 

 is separated from - by a long diastema ; a , 3 - 

 and A are of transversely oval shape and quite 

 compressed antero-posteriorly ; of these teeth 

 A is the largest and - the smallest ; A is much 

 the smallest of the entire molariform series and 



1 r .-. r iVPC <Jl naviuuvs \iuvinuirit- 



has a remform masticating surface, convex in .'? . . 



num) aguirrei, X f . La rlata 



front and concave behind ; the interspaces be- Museum. 



tween the teeth are unusually long. Aside 



from -, the two series of upper teeth are nearly parallel and converge but 



little posteriorly. 



MEASUREMENTS. 



Upper dentition, length 063 



" " 2 036 



J-, length (z. ^..antero-posterior diameter) .007 



" width (i. e., transverse diameter) 005 



2., length 007 



" width on 



FIG. 31. 

 Type of Hapalops (Tapinothe- 



length 008 



width 01 1 



length 0065 



width oio 



length 005 



width 0073 



