682 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



distally shorter than ectocuneiform; (6) enlargement 

 of Mts IV and reduction of Mts II indicating that 

 the main weight is carried upon the third and fourth 

 digits (D. 3 and D. 4), the second digit (D. II) being 

 relatively reduced; (7) corresponding reduction of Mts 

 II and sharply convex ridge on its anterior face, as 

 in Brontops rohustus (type); (8) striking narrowness 

 or reduction of terminal phalanges, which are even 

 narrower than the middle phalanges. 



The specific characters of this pes (those of M. 

 proutii or M. heloceras) are (1) simple, oval shaft 



defined facet for Mts III, the displacement being 

 rather incipient; (6) similarly ectocuneiform deep- 

 ened (vert. 23, tr. 35), with a characteristic pair of 

 ectal facets for the cuboid and a double pair of ental 

 facets for the mesocuneiform and Mts II, respectively; 



(7) mesocuneiform correspondingly shallow (vert. 16, 

 tr. 23, ap. 36) for the support of the reduced Mts II; 



(8) the shaft of Mts IV considerably exceeds that of 

 Mts III in stoutness and greatly exceeds that of Mts 

 II; (9) Mts III (length 175 mm.) is distinguished 

 by a deep antero-internal groove in the superior 



Bi "^^^ ^ Ai 



Figure 614. — Manus of Menodus trigonocerasf 



A, Am. Mus. 1079 (compare fig. 613): Ai, Front view, cuneiform restored; Aj, ptialanges of digit III; Aj, top view of carpus. B, .\.m. Mus. 515; 

 Bi, Manus, front view (lunar and magnum incorrectly restored); Bi, phalanges of digit III. One-fourth natural size. 



of the tuber calcis, the entire length of the calcaneum 

 being 158 milUmeters; (2) relatively narrow (22 mm.) 

 displacement of the astragalus upon the cuboid; 

 (3) total width of 191 millimeters of the combined 

 distal facets of the calcaneum and astragalus; (4) navi- 

 cular relatively deep, measuring 22 millimeters 

 vertically, 58 transversely, with broad (35) ectocune- 

 iform and relatively narrow (19) mesocuneiform 

 facets; (5) cuboid relatively deep (vert. 35, tr. 45) 

 with broader calcaneal than cuboidal facets prox- 

 imally, an extremely large facet (tr. 37, ap. 47) 

 for the enlarged Mts IV, and a relatively small, ill- 



portion of the shaft, and Mts II (length 156) has a 

 subtriangular section, owing to the anterior ridge and 

 grooving and flattening of the outer side facing toward 

 Mts III. 



Among the chief primitive and specific characters 

 of this pes are, therefore, the relatively narrow dis- 

 placement of the astragalus and cuboid and of Mts II 

 and Mts III against the cuboid and ectocuneiform 

 respectively. 



The proximal phalanges of D. 2 and D. 4 are 

 relatively elongate and are laterally compressed, a 

 striking; feature of this re2;ion being that the middle 



