618 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



sided, and it formed a more open angle with the 

 cuboid facet; the calcanea show corresponding differ- 

 ences. But these differences are accompanied by 

 many general resemblances that indicate the annec- 

 tent or primitive character of the pes in question. 



Comparison with Manteoceras is made difficult by the 

 scantiness of the material referable to that genus. The 

 femur is of nearly the same length as in the young male 

 Manteoceras (Am. Mus. 1587), but the third trochanter 



Figure 529. — Left hind limb of Limnohyops monoconus (doubt- 

 fully referred) 

 Am. Mus. 11690; Bridger B 1. A', Front view; A^, outer side view. One-sixth 



natural size. 



seems smaller; the tibia is absolutely and relatively 

 longer, its proximal end is narrower, its distal end is 

 broader; the patellar facet is decidedly longer and 

 more anterior than in Manteoceras. The astragalus, 

 as compared with that of the young Manteoceras (Am. 

 Mus. 1587), offers the following differences: The inter- 

 nal trochlear ridge is angulate rather than broadly con- 

 vex; the ectal facet is shallower, less produced on its 

 lower internal border; the sustentacular facet is much 

 longer: the cuboid facet is decidedly smaller; the navic- 

 ular facet not so deep anteroposteriorly. As compared 

 with the astragalus of the old female Manteoceras? 



(Am. Mus. 12204) most of the above-described differ- 

 ences also hold good, save that the siz(3 in Am. 

 Mus. 11690 is considerably greater and the navicular 

 facet seems proportion- 

 ately deeper rather than 

 shallower. 



Conclusion. — In brief, 

 the hind limb under 

 consideration appears 

 to belong neither with 

 Palaeosyops, Mesatirhi- 

 nus, nor Manteoceras. 

 On the other hand, it 

 appears not to differ gen- 

 erically from Am. Mus. 

 11689, described above, 

 and together with that 

 specimen it may repre- 

 sent a Bridger B mem- 

 ber of the Limnoliyops 

 phylum. 



Limnohyops laticeps 



Many parts of the 



skeleton of i. laticeps are 



fortunately preserved 



with the type skull in 



the Yale Museum (No. 



11000). The geologic 



level is probably Bridger 



C or D, at Henrys Fork 



Hill, Bridger Basin, Wyo . 



Cervicals. — The axis and four other cervicals (C. 3, 



C. 5, C. 6, C. 7) are preserved; the fourth cervical is 



missing. The epiphyses are mostly detached, indicat- 

 ing a juvenile condition. 

 The axis (C. 2) and third 

 vertebra (C. 3) especially 

 have large inferior keels or 

 hypapophyses. The third 

 to sixth cervicals exhibit 

 broadly depressed inferior 

 lamellae. The seventh 

 (C. 7) is irnper forate 

 exhibiting narrow, rodlike 

 transverse processes with- 

 out inferior lamellae. 



Dorsals. — The median 

 dorsals exhibit centra 

 angulate but not keeled 

 inferiorly. In one of the 

 posterior dorsals the cen- 

 trum is slightly keeled and 

 the spine is elevated (112 



mm.) above the base of the centrum. 



Lumhars. — The lumbars preserved are apparently 



the second and the fourth (L. 2, L. 4); the first, third 



Figure 530. — Right pes of lAm- 

 nohyops monoconus? 



.\m. Mus. 11689; Bridger B 2. Ai, Front 

 view; A2, outer side view of tarsus; A3 

 phalanges of median digit. One-third 

 natural size. 



FiGuiiE 531. — Ventral surface 

 of sacrum of Limnohyops 

 laticeps 



Yale Mus. 11000 (type); Bridger C or 

 D. One-third natural size. 



