EDENTATA OF THE SANTA CRUZ BEDS. 2 1 I 



Metacarpal IV, proximal width on Calcaneum, distal width 027 



" " distal width . . '. OI2 " width at constriction 020 



Femur, length from head 2OI Navicular, length on tibial side 013 



" " " great trochanter ... .196 " " " fib ular side oio 



" proximal width 071 " width 024 



" distal width over tuberosities . . . .062 Metatarsal IV, length 049 



" " " " condyles 055 " " proximal width 014 



" width of rotular groove 030 " " " thickness 023 



Calcaneum, length 071 " " distal width 013 



" proximal width 053 " " " thickness 019 



The specimen upon which the foregoing description is founded was col- 

 lected by Mr. Hatcher at Corriken Aike on the coast of Patagonia. 



HAPALOPS GRAND^VUS Mercerat. 



(Plate XLIII, Figs. 6, 6".) 



grandcevus Mercerat; Rev. del. Mus. de La Plata, T. II, 1891, 



P- 13- 



This species is very close to H. indifferens and may indeed be refera- 

 ble to it, but the differences would appear to be quite constant. The fol- 

 lowing description is drawn chiefly from a well-preserved mandible in the 

 American Museum of Natural History (No. 9538) which agrees quite 

 closely with Mercerat's type in the La Plata Museum. The first lower 

 tooth, which in H. indifferens is of the usual subcylindrical form, in the 

 present species is markedly trihedral, with the base of the triangle 

 directed inward and slightly backward and the apex outward and slightly 

 forward, two vertical sulci, one on the outer side near the posterior border 

 and the other on the inner side near the anterior border, give the tooth a 

 characteristically fluted or columnated appearance. 



The other teeth are like those of H. indifferens; ? and ^are transverse 

 and rectangular, though a little broader on the internal and on the exter- 

 nal side, and T is irregularly cylindrical and of curiously different shape 

 on the two sides of the jaw. 



The mandible differs from that of H. indifferens in a number of respects, 

 the most obvious of which is the somewhat shorter predentary beak, which 

 has a more flared and depressed dorsal border. The condyle is set upon 

 a shorter neck, narrowing the notch between condyle and angle ; the pos- 

 terior border of the coronoid process is more curved, and the postero- 



