O shorn. Skeleton of Coryphodon radians. 83 



Description of Skeleton. 



Composite of nine individuals, all from the Big Horn Beds, as follows : No. 

 2S67 ; skull, left humerus, left mtc. I and ectocuneiform ; caudals 1-3, lo-ii. 

 No. 2867, lower jaw. No. 2829 ; right scapula and fore-limb complete ; left 

 scapula, magnum, trapezium, trapezoid, metacarpals I-V and phalanges. No. 

 2865 ; all cervical vertebrde, dorsals and ribs 1-9 complete, 3 phalanges of right 

 pes. No. 2963 ; dorsals 10-15 and ribs complete, lumbars 1-5 complete, pel- 

 vis, left pes (excepting mts. I, III-V, and ectocuneiform). No. 2869 ; right 

 hind limb complete (excepting mts. IV-V and 3 phalanges. No. 4329, left 

 ulna, femur and tibia. No. 258 ; caudals 4, 5, 8. Sternals complete from No. 

 2825. Restored : left radius, left fibula, right mts. IV-V, left mts. III-V, cau- 

 dals, 6, 7, 9, and 12-22. 



In general one is struck l)y the very large size of the head, 

 formidable front teeth, the shortness of the ribs, the heavy char- 

 acter of the girdles, the heavy limbs, and the semiplantigrade or 

 subdigitigrade condition of the feet. It is probable, as already 

 shown by the writer, that in the hind foot the calcaneum nearly 

 touched the ground in the forward step. 



The skull presents a very peculiar appearance with its power- 

 ful and spreading upper and lower canines, and widely spaced 

 incisors, slender zygomatic arch and broad, flattened cranium. 

 The following characters distinguish this specific type : Premaxil- 

 laries short, not reaching nasals ; free portion of nasals short ; 

 nasals projecting between maxillaries, and then spreading upon 

 inner side of frontal tuberosities ; naso-frontal suture disap- 

 pearing posteriorly ; maxillaries occupying a broad area and bulg- 

 ing out opposite the canine alveoli and concave behind; lachry- 

 mals not clearly defined ; f rontals above the orbits supporting two 

 prominent knobs or convexities, confluent with parietals poster- 

 iorly ; parietals expanding above middle portion of temporal 

 fossa, and lateral parietal crest thickening, as indicative of a rudi- 

 mentary parietal horn ; mid-parietal region depressed and 

 extremely rugose for muscular attachment {occipito-frontalis) ; 

 malars extending to the front of orbit, exhibiting a downward 

 masseteric process slightly behind the orbit, expanding widely but 

 slender in section ; postglenoid processes for squamosal rather 

 slender; external auditory meatus widely open, and paroccipital 

 and posttympanic region compressed into a narrow ridge; occiput 



