2O8 PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 



HAPALOPS INDIFFERENS Ameghino. 



(Plate XXXIV, Figs. 1-5.) 



Hapalops indifferens Amegh. ; Enumeracion sistematica, etc., 1887, p. 22. 

 Hapalops ( ? ) indifferens Mercerat; Rev. del Mus. de La Plata, T. II, 



1891, p. 13. 

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



Ill, 1894, p. 99. 



The type of this species, which is in the La Plata Museum, is an incom- 

 plete right mandibular ramus, with the first tooth broken to the level of the 

 jaw and the other teeth missing. To this species may be referred an indi- 

 vidual in the Princeton collection (No. 15,110), which agrees very well 

 with what is preserved of the type, save in regard to the position of the 

 mental foramen, which in the latter is remarkably far forward, but this is 



FIG. 31. 

 Type of Hapalops indifferens, x \. La Plata Museum. 



doubtless individual merely. The specimen consists of the anterior half 

 of the skull, with mandible complete and all the teeth in place ; one cer- 

 vical, ten thoracic, two lumbar and one caudal vertebrae ; the left ulna, 

 lacking the distal epiphysis, and metacarpals II-IV of the left manus ; the 

 left femur and a considerable portion of both hind-feet. 



In the upper jaw A is smaller than that of H. longiceps and of more oval 

 section, and is implanted farther behind the maxillo-premaxillary suture ; 

 the remaining upper teeth differ little, save in size from those of the last 

 named species ; * and A are usually more rectangular, while - has a more 

 oblique position and has no vertical groove on the posterior face. In 

 some individuals the outer side of a , a and A displays a vertical sulcus. 

 Of the lower teeth T is small, erect, of oval cross-section and is separated 

 by a short distance from ^ ; % and ^ are transverse and rectangular and i. 

 is subcylindrical. 



