614 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



the motions were slower than in either the American 

 or Asiatic species of Tapirus. Palaeosyops entered a 

 graviportal line of evolution, but Limnohyops was 

 more conservative. Its feet become mesatipodal 



Limnohyops? monoconus, Am. Mus. 11699 (manus, radius, and 



ulna, figs. 525 B, 527) ; Bridger B 2. 

 Lhnnohyo-ps? monoconus, Am. Mus. 11690 (complete hind limb, 



fig. 529); Bridger B 1. 



Measurements of limb hones of Limnohyops laiiceps 

 and L. monoconus, in millimeters 



L. lati- 

 ceps, 

 Yale 

 Mus. 

 11000 

 (type) 



Humerus, length 



Radius, length I 230 



Radius, breadth, I 

 proximal I 53 



Radius, breadth. 



distal 



"Ulna, length 



Carpus, width 



Mtc II, height 



Mtc III, height 



Mtc III, distal width 



(maximum) 



Mtc IV, height 



Mtc V, height 



Femur, length 



Tibia, length 



60 

 307 



L. ?monoconus 



Am. 

 Mus. 

 11689, 

 Bridger 

 B2 



295 

 230 



58 



55 

 312 

 "75 



99 

 109 



33 



357 



285 



Am. 



Mus. 



11690, 



Bridger 



Bl 



55 

 308 



103 



34 

 97 

 79 



387 

 297 



Figure 521. — Astragali of Eocene titanotheres 



A, Lambdother'mm popoagkum; B, EotUanops borealis; C, Limnohyops monoconus: D, Palaeosyops 

 robustiis; E, Manteoceras manteoceras; ¥ and G, Mesatirhinus petersoni; H, Metarhinus cf. M. 

 earlei; I, DoUchorhinus hyognaikus. Ai, Bi, etc., front view; A2, B2, etc., back view. Astragalc- 

 calcanealfacets: ectal (ed), sustentacuiar (stw), and inferior (in/); astragalon»vicalar facet (m); 

 astragalocuboidal facet (c6). One-third natural size. 



rather than brachypodal, and the limbs throughout 

 are narrower and more slender than those of Palaeo- 

 syops. The hand and foot were relatively elongate — 

 that is, they were appressed rather than spreading. 

 The ungual phalanges are truncate, expanding dis- 

 tally, rather than rounded and obtuse, as in Palaeo- 

 syops. These animals present many adaptive 

 resemblances to Mesatirhinus in the manteoceratine 

 subfamily, yet so far as known the parts are somewhat 

 heavier and more robust throughout. 



The materials of Limnohyops are as follows: 



Limnohyops laticeps, Yale Mus. 11000 (type skuU and parts of 

 skeleton, PL LVII, figs. 261 B, 264, 531, 532); Bridger D (?). 



Limnohyops? monoconus, Am. Mus. 11689 (vertebrae, fore and 

 hind limbs, figs. 525 A, 530) ; Bridger B 2. 



Two skulls of Limnohyops have been found 

 in Bridger B, namely, L. prisons and L. 

 monoconus, the latter an animal of consider- 

 able size. Parts of three skeletons in the 

 American Museum collection (Nos. 11689, 

 11699, 11690) belong, possibly, to L. mono- 

 conus. The generic reference to Limnohyops 

 is well assured; the specific reference is 

 doubtful. The ground for the generic refer- 

 ence of the skeletal specimens to Limnohyops 

 is their agreement in many details with the correspond- 

 ing bones of the type skeleton of L. laticeps, namely, (1) 

 the distal end of Mtc III of the type agrees with Mtc 

 III of Am. Mus. 11699; (2) the radius of Am. Mus. 

 11689 agrees in length and in details of character with 

 the radius of the type; (3) the ulna of Am. Mus. 

 11689 agrees closely with that of the type of L. laticeps, 

 especially in the rugose area of the olecranon. 



Limnohyops monoconus? 



Incomplete skeleton from Bridger B 2, Grizzly Buttes, Bridger Basin, Wye, 

 Am. Mus. 11689 



The material includes the atlas, a cervical, several 

 anterior dorsal vertebrae, the humerus, radii, ulnae, 

 incomplete manus and pes, femur, tibia (figs. 510,. 



