56 



should have scarcely veutured upou a couclusion as to their specific 

 distinction from the Dinomis giganteus or Dinomis robustus, the 

 coįrespondence of configiiration being so close, and the difference of 

 size so slight. 



The articular surface is contiuued from the head upon the upper 

 part of the neck, expanduig as it approaches the great trochan- 

 ter, along the summit of which it is terminated by a ridge. In 

 both species the surface for attachment of the hgamentum teres is 

 formed, as it were, by a portioii of the iuner aiid back part of the 

 hemisphere ha^dng been cut oflp obliqiiely with a sUght excavation. 

 The correspoūding hgainentous surface in the head of the femur of 

 the Dinomis crassus is relatively smaller, less depressed and less 

 defined. The upper and fore part of the trochanter is less produced 

 relatively to the breadth of the supra-trochanterian articular surface 

 in the Dinomis elephantopus. In this species the sub-circular rough 

 surface for the attachment of the iliacus intemns musele is relatively 

 nearer to the head of the bone than in the Dinomis robustus ; the 

 rugged and thick fore part of the great trochanter desceuds lower 

 upon the shaft ; indeed, the shortuess of the entire bone seenis to 

 depend chiefly on the shaft being relatively shorter in the Dinomis 

 elejihantopus. The intermuscidar ridge continued from the tro- 

 chanterian one seems to bifurcate sooner in the Dinomis elephantopus. 

 The depression behind the trochanterian ridge is less deep in the 

 Dinomis elephantopus. The oblique rotular channel is relatively as 

 vvide and deep as in the Dinomis robustus, but the inner boundary 

 formed by the fore part of the inner condyle is shorter. 



At the back part of the shaft the medullo-arterial foramen is 

 relatively nearer the proxinial end of the bone ; the two tuberosities 

 belovif this are closer together. The two sides of the fibular groove 

 are at a more open angle, and the groore is less deep in the Dinomis 

 elephantojjus, the outer side being less produced. 



The antero-posterior breadth of the outer and inner condyles is 

 ecįual in the Dinomis eJephantopus as in the Dinomis i'obustus ; but 

 in the Dinomis crassus that dimension of the outer condyle exceeds 

 the šame dimension in the inner one, and the fibular groove is more 

 open or shallow than in the Dinomis elephantopus. 



The generic modifications of the femur are, however, very closely 

 preserved in each species, being strictly of the type ascribed to the 

 genus Dinomis in my origiual memoir, Zool. Trans. vol. iii. p. 247. 



Dimensions of the tibia in D. robustus. D.eUjthantopus. D. crassus. 



Ft. In. Lines. 



Leiigth 2 8 3 



Trausverse breadth of proximal end 7 6 



Fore-and-aft breadth of do 4 9 



Leastcircumferenceof shaft 6 9 



'Iraiiiverse breadth of distal end... 4 4 



The «.\tiemes of size in a series of several bones are here given. 



In. 



r2 O O \ 



tl 9 6* J 



{? n 



f 4 6*1 



14 3 I 



6 5 



Ft. In. Lines. 



17 6* 



16 6 



6 2 



3 6 



4 10 

 3 3 



