1857.] OWEN PLIOLOPHUS VULPICEPS. 69 



at the fore and inner part of the articular head, and not so low down 

 as in the humerus from the " terres noires du Laonnais," ascribed 

 to Lophiodon by Cuvier *. 



The deltoid surface is short : a smooth oblique tract separates it 

 from a second low oblique (pectoral) ridge ; the shaft of the bone 

 rapidly contracts below the head, where it is not so compressed or 

 so broad from before backwards, as in Palceotherium ; it is thicker 

 transversely than in Hyracotherium. 



The supinator ridge begins at about the lower third of the bone, 

 is moderately sharp for about 9 lines, and then subsides into a rather 

 rough flattened surface above the inner condyle ; it is very slightly 

 produced. The bone is perforated above the lower articular surface ; 

 this surface has one depression and two prominences, as in the 

 Perissodactyles. The general shape and proportions of the bone are 

 like those of the humerus of the Hyrax. 



Femur : PL IV. figs. 5 to 9. — The femur is rather more than 

 H inches in length : its most important character, as indicative of the 

 affinities of the Pliolophus in the ungulate series, is the continuation 

 of the outer ridge of the great trochanter vertically down the outer 

 border of the shaft and its development into a third trochanter, t f , 

 which subsides before it reaches the mid-length of the bone. The 

 great trochanter rises in an obtusely pointed form 5 lines above the 

 articular head ; and it developes a tuberosity at the fore part of its 

 base. The neck sinks behind the head before it rises into the tro- 

 chanter. The small trochanter is a longer ridge than in the Hyrax : 

 the shaft below the trochanter becomes less flattened than in the 

 Palaeotheres or Lophiodons : the transverse section gives a kind of 

 semi-ellipse with the flatter side slightly convex : it shows a com- 

 pact wall of bone of about a line or a line and a half thick, and a 

 medullary cavity of from 3 lines to 4 lines in diameter. At about 

 2 inches from the distal end the shaft begins to expand and become 

 three-sided, the hind- and the out-sides being less convex and broader 

 than the inner side ; then an anterior surface is established by the 

 beginning of the rotular groove, about an inch and a half from the 

 lower end : the inner border of the groove is produced and sharp ; 

 the outer border was broken oif in the extraction of the bone : the 

 condyles are produced backward, but not so much forward as in 

 Palceotherium : the inner surface of the expanded condyloid end of 

 the bone, PI. IV. fig. 8, is flat, with a much less prominent part for 

 the internal lateral ligaments than in Tapirus 3 Hyrax, or Palceothe- 

 rium. The popliteal depression is very slightly concave transversely : 

 it is divided from the intercondyloid fossa by a ridge continued in- 

 ward from the back of the outer condyle. 



Tibia: PI. IV. figs. 10-13. — The tibia, which was extracted 



* Ossemens Fossiles, ed. 8vo, torn. iii. p. 411. pi. 79. f. 6 & 7. 



t " Les pachydermes qui offrent cette particularite sont les rhinoceros, les tapirs, 

 les chevaux et jusqu'a un certain point les damans, c'est-a-dire les genres que 

 j'ai designes comme forroant une petite famille distincte, et a systeme de doigts 

 impairs au pied de derriere ; et c'est precisement a cette famille qu'appartiennent 

 les Palaeotheriums, par tous les autres rapports." — Cuvier, Ossemens Fossiles, ed. 

 1835, 8vo, torn. v. p. 287. 



