HTEACOTHEEIUM. 643 



proximal articular face as in T. cuhitalis, not a concavely excavated one as 

 in H. eximius. It differs from that of the former species in having the pisi- 

 form facet largely facing posteriorly instead of proximally. The external 

 face of the unciform is larger than that of the cuneiform, and nearly as 

 large as that of the scaphoid, and is subquadrate in form. Its lunar facet 

 is not large. The lunar and scaphoid facets of the magnum are subequal. 

 It rises in a compressed arch posteriorly, and has the usual long decurved 

 tuberosity posteriorly. The trapezoides has no posterior tuberosity, re- 

 sembling in this respect the Hyrachyus eximius, and differing from the Trip- 

 lopus cuhitalis, where it is present. The trapezium is a small bone represent- 

 ing a liemisphere with one end cut off. It has about equal facets for the 

 scaphoid and trapezoides. The pisiform is spoon-shaped with a stout neck, 

 and the two proximal facets. It has a nuich thinner distal edge than either 

 of the other species above mentioned, which is much more expanded than 



in the H. eximius. 



Measurements of carpus. 



Length of carpus ak lunar 0120 



Width of carjnis at proximal row 0160 



Diameters of scaphoid) f"^, .,.. 



{ depth OIUU 



I length 0076 



Diameters of lunar < median width 0055 



( depth (greatest) 0080 



^. ^ „ .„ (length 0068 



Diameters of cuneiform < , " , . .. . 



< depth 0070 



Length of pisiform 0100 



Width of pisiform distally 0060 



„. . ., < length 0040 



Diameters of trapezium < , =>. „.^.. 



(depth 004o 



I length infiont 0iJ35 



Diameters trapezoides< width in front 0035 



( depth 0060 



f length in front *. 0050 



„. ^ length at middle 0075 



Diameters of magnum { .?., . e ^ nn-n 



" width in front 00.^0 



l^ depth 0096 



/ length ■ 0070 



Diameters of unciform .? width 0070 



( depth 0055 



The femur is much like that of Pliolophus vulpiceps figured by Owen,^ 

 and that of P. vintanus figured by myself^ The great trochanter is acumi- 



' Quarterly Journ. Geolog. Soc, XIV, PI. IV. 



'' Report U. S. G. G. Surv. W. lOOtU Mer., IV, Pt. II, PI. XLV. 



