BY C. W. DE VIS. 



95 



a feeble concavity of this side of the hone, and the articulating 

 surface extending upon the elevation obtains therefrom a little 

 curvature. In the Varans the prominence of the angle becomes a 

 conspicuous and distinctive character, related to the greater develop- 

 ment in size and function of the pisiform bone articulated with it, 

 consequently to the needful power of the manus in these heavy- 

 bodied climbers and deep ovipositors ; the general form of the 

 articulating surface is now lunate or reniform, but its ulno-palmar 

 end on which plays the pisiform is in some species — V* rarius for 

 example — determined as a separate facet by a more oblique and 

 comparatively flattened surface. Tin's facet and the bold prominence 

 on which it is seated are well-marked features of the fossil bone. 

 As in Varanus the protuberance ends abruptly proximad ; on its 

 radial side it sinks deeply to the general level of the head, from 

 which again rises a coarsely sculptured tuberosity occupying the 

 whole of the radio-palmar angle : a tubercular surface similarly 

 placed is seen in Varanus, but in niueh less prominence, and with, 

 of course, much less pronounced separation from the articular head. 



The proximal surface corresponding to the greater sigmoid 

 cavity is a basin of remarkable breadth for the reception of the 

 much-dilated ulnar condyle of the humerus to which it is further 

 conformed by its unusual shallowness. On its free sides it is 

 bordered by a broad and rough lip overhanging the shaft on the 

 ulnar side, and at its proximal end surpassing the height of the 

 olecranon. The shape and extent of the surface for the head of the 

 radius is obscured by the loss of the coronoid process, but it seems 

 not to have reached quite so far towards the olecranon as in 

 Varanus. The olecranon itself scarcely differs in form and degree 

 of development from that of V. rarius. The braehialis anticus 

 is upon a rough oval tubercle placed with the same obliquity to the 

 long axis of the bone as in Varanus. The massive ruggedness of 

 the bone throughout bears testimony to the great power and almost 

 mammalian activity of its investments during life. 



Tabulating the measurements of this bone, and of the humerus, 

 with reference to their co-ordinates in T". rarius, we obtain in- 

 structive figures : — 



