626 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Mts IV, a very distinctive feature of this pes, which 

 enables us to distinguish it from that of Amynodon. 



The metatarsals, like the metacarpals, are moder- 

 ately long, have flattened shafts, and are widely 

 expanded distally. The vertical measurements are, 

 Mts II, 103 millimeters; Mts III, 110; Mts IV, 103; 

 Mts III, distal breadth, 43. Mts II shows a postero- 

 lateral facet to which a vestige of Mts I was probably 

 attached. As regards displacement Mts IV and III 

 are "serial," articulating solely with the cuboid and 

 ectocuneiform respectively; Mts II, on the contrary, 

 is "displaced," with a prominent internal process and 

 abutment against the ectocuneiform. 



The spread of the phalanges distally as moimted is 

 181 millimeters. The proximal phalanges are much 



'?/!«k; /cuSI — ' ^-^ (cull) (navj 



Figure 541. — Relations of the ectal, sus- 

 tentacular, and inferior facets of the as- 

 tragalus and calcaneum in Palaeosyops 

 One-third natural size. 



the largest and longest in D. Ill; the first phalanx 

 has a length of 39 millimeters; the second, which 

 exhibits a sharply upturned distal facet, has a length 

 of 25; the third is restored, but the distal phalanx of 

 D. IV, measuring 33 millimeters in length and 35 

 in breadth, is spreading and distally cleft. 



Measurements of the composite mounted skeleton of Palaeosyops 

 leidyi {Am. Mus. 1544) 



Skeleton: Millimeters 



Total length, pmx to tail drop 2, 007 



Total length, pmx to ischial tuberosity 1, 980 



Total height, top of third dorsal spine 1, 090 



Total height to top of scapula 1,010 



Total length along vertical column 2, 083 



Skull: Millimeters 



Total length, incisors to occipital condyle 415 



Total breadth, transverse zygomata 310 



Vertebral column, length: 



27 presacral vertebrae 1, 230 



7 cervicals 320 



Midcervical centrum 34 



17 dorsals 820 



Fourth dorsal centrum 38 



Fourth dorsal, height of spine 163 



3 lumbars 148 



Second lumbar centrum 47 



4 sacrals 159 



19 caudals (partly restored) 615 



Ribs: 



Fifth rib, outer curve 545 



Eighth rib, outer curve 620 



Scapula : 



Length 345 



Greatest width 220 



Pelvis : 



Os innominatum, total length 465 



Width across ilia 488 



Fore limb, total length 810 



Humerus, total length 325 



Radius, total length 235 



Ulna, total length 315 



Carpus, top of lunar to bottom of magnum 50 



Carpus, width 96 



Manus, length, lunar to tip of D. Ill 250 



Digit III, length of metacarpal 113 



Digit III, breadth of metacarpal 45 



Hind limb, total length 940 



Femur, total length 370 



Tibia, total length 290 



Pes, total length, os calcis to tip of D. Ill 340 



Tarsus, height, calcaneum to ectocondyle 76 



Astragalus, height, inner face 58 



Astragalus, breadth, distal end 48 



Calcaneum, total length 100 



Calcaneum, total width 63 



Mts III, length 110 



Palaeosyops robustus 



The characters of the postcranial skeleton of P. 

 robustus, so far as known, seem to differ but little 

 from those of P. leidyi. In the composite skeleton 

 of P. leidyi (Am. Mus. 1544) many of the vertebrae, 

 ribs, and parts of the feet and limbs seem to agree 

 in size with the remaining parts associated with the 

 P. leidyi type skull and yet are themselves associated 

 with skulls and teeth referred to P. robustus. 



The seven vertebrae (fig. 544) associated with a skull 

 of P. robustus (Am. Mus. 1580) and used in restoring 

 the vertebrae of the skeleton P. leidyi agree with those 

 of Manteoceras but are nevertheless remarkable in this 

 respect — that the flange on the pleurapophysis of 

 C. 6 was much weaker than that in the rhinoceroses, 

 tapirs, horses, and most placental mammals. The 

 pleurapophysial flange on C 5 was expanded; it is 

 incompletely preserved, but it does not appear to 

 differ greatly from that of Manteoceras or of Doli- 

 chorMnus. In C. 4-C. 7 the prezygapophyses and 

 postzygaophyses face, respectively, obliquely inward 



