REPTILIA: VARANOSAURUS 103 



have been found in connection with the carpus, but more or less 

 disturbed in their relations. The complete, or nearly complete, 

 carpus has been found in three specimens, with more or less of the 

 metacarpals and phalanges in anatomical association with them, so 

 that their positions are positively assured, as also their relations 

 with the forearm. The carpus is of the same general structure as 

 that of Ditheirodon (Plate VII) save that the outer centrale and fifth 

 disiale were never ossified. Although the pisiform in Dimetrodon 

 has never been found in place I doubt not that it has the same 

 articulations as in Varanosaurus, Casea, Limnoscelis, Trispondylus, 

 etc., articulating in the interval, as in modern reptiles, between the 

 ulna and ulnare. In the different carpi found with the bones in 

 place there is a small interval between the radiale and the first 

 and second carpalia, doubtless filled out in life by a small cartilage 

 representing the unossified centrale, quite as in the hind feet. And 

 this is also the case with the fifth carpale. Although several carpi 

 have been examined with carpals and metacarpals all in place and 

 in the positions shown in the drawing, there is invariably a small 

 unossified space at the proximal end of the fifth metacarpal. As it 

 is altogether improbable that this carpale should have been lost in 

 all these specimens, I am quite assured that it was never ossified. 

 The fifth finger is more reduced than is the fifth toe, and doubtless 

 this explains the vestigial condition of the carpale. 



The metacarpal of the first finger is very small, and the finger 

 is very short. This finger, with the bones articulated, has been 

 observed in two different specimens quite in the position given in 

 the figure, closely appressed to the second finger, and this doubtless 

 was its normal position in life. The much-elongated fourth meta- 

 carpal in itself indicates an elongated fourth finger, and the pha- 

 langes preserved, if I have correctly placed them, substantiate the 

 conclusion. The ungual phalanges are quite like those of the hind 

 foot, strong and well curved. In the drawing the phalanges not 

 found in actual relations are shown by the uniform shading; and 

 two or three of the distal ones are conjectural. 



Pelvic girdle and extremity (Plates IX-XIII). — The pelvis of 

 Varanosaurus is noteworthy for the small size of the ilia and the large 

 size of the pubes and ischia, suggesting the pelvis of the Sauropte- 



