X LIST OF TEXT ILLUSTRATIONS. 



Fig. 17. Skulls of Santa Cruz Gravigrada, top view, x . a, Hapalops longiceps ; b, 

 ff. ructimeycri ; c, Megalonychothcrium atavus ; d, EucJwlaeops fronto ; e, 

 Analcimorphus giganteus ; /, Schismothctium fractum ; g, S. splendens ; //, 

 Planops magnus . . . . . . . . . . . 165 



Fig. 1 8. Occiputs of Santa Cruz Gravjgrada, x \. a, Hapalops longiceps ; b, Eucholoe- 



ops fronto ; c, Hapalops dongatus ; d, Pelecyodon cristatus . . . . 166 



Fig. 19. Mandibles of Santa Cruz Gravigrada, x . a, Hapalops indifferent ; b, H. 

 rostratus ; c,H. elongatus ; d, Eucholceops fronto ; e, Schismotherium fractum 

 (marked S. spletidens f) ; /, Prepotlicrium moyani ; g, Ncmatherium angula- 

 tum (marked N. sp.) .......... 167 



Fig. 20. ? Hapalops sp. Right scapula, x \ . . . . . . . . 169 



Fig. 21. Hapalops ructimeycri, pelvis from the ventral and right sides, x \ . . . 170 

 Fig. 22. Humeri of Santa Cruz Gravigrada, x \. a, Hapalops longiceps ; b, H. ructi- 

 meycri; c, Pelecyodon arcuatus ; d, f Nematherium sp. . . . . 171 



Fig. 23. Hapalops longiceps, a, left ulna, x \. b, left radius, x \ . . . . 172 



Fig. 24. Hapalops longiceps, left manus, x \ . . . . . . . 172 



Fig. 25. Bones of the hind limb of Santa Cruz Gravigrada, x \. a, Hapalops (femur of 

 H. elongatus, tibia and fibula of H. longiceps); b, Analcimorphus giganteus 

 (marked A. leptocephalus) ; c, Prepotherium potcns . . . . . 173 



Fig. 26. Pes of Santa Cruz Gravigrada, x \. a, Hapalops longiceps ; b, Analci- 

 morphus giganteus (marked A. leptoccphalus) ; c, Pelecyodon arcuatus . . 1 74 

 Fig. 27. Dorsal side of right astragalus, nat. size, a, Hapalops elongatus ; b, Prepo- 

 therium potens . . . . . . . . . . . 175 



Fig. 28. Distal end of right calcaneum, nat. size, a, Hapalops elongatus ; b, Prepo- 

 therium potcns ........... 176 



Fig. 29. Type of Hapalops rectangularis, x \. La Plata Museum .... 206 



Fig. 30. Type of Hapalops ellipticus, x \. La Plata Museum ..... 206 



Fig. 31. Type of Hapalop s indifferens, x {. La Plata Museum 208 



Fig. 31. Type of Hapalops (Tapinothcriuni) aguirrei, x f . La Plata Museum . . 213 

 Fig. 32. Type of Hapalops aguirrei, x f. La Plata Museum . . . . . 214 



Fig. 33. Eucholceops ciirtus, type, x \. Ameghino collection ..... 277 



Fig. 34. Euchoteops curtus, type, x \. Ameghino collection ..... 277 



Fig- 35- Schismotherium fractum, mandible, x \. Ameghino collection . . . 302 

 Fig. 36. Schismotherium fractum, left manus, x \. Ameghino collection . . . 302 

 Fig. 37. Pelecyodon cristatus, mandible, x \. Ameghino collection .... 309 



Fig. 38. Ncmatherium sp., left astragalus and left calcaneum, x \. Ameghino 



collection ............ 350 



Fig. 35.' Phalanges of digit III., left manus of Necrolcstes patagonensis, x \. a, from 



ulnar side ; b, from dorsal side . . . . . . . . 376 



Fig. 36.' Femur of Necrolcstes patagonensis, x \ . a, front view ; b, rear view . . 377 

 F'g- 37-' Grinding teeth of Myocastor coypus, crown view, x \. a, right upper teeth ; 



b, right lower teeth 390 



Fig. 38.' Skulls of Octodontidae, side view, a, Myocastor coypus, x ; b, Capromys 



fournieri, x \ ; c, Ncorcomys australis, x f . . . . . . 391 



1 Through an oversight these numbers have been duplicated. 



