ART. :i3. AN EXTINCT VAEANID LIZARD GTLMORE. 15 



borders. The base of the teeth are finely striated. The striations 

 Owen ^ observes in Varanus are " produced by inflected folds of the 

 external cement, as in Ichthyosnumis and Lahyrlnthodon^ but they 

 are short and straight as in the former genus." 



The teeth throughout both upper and lower series are smaller than 

 in a living Varanus salvator of the same size, and whereas there are 

 12 teeth in both the maxillae and dentaries of a Varanus salvator^ in 

 Saniwa there are not less than 14, probably more teeth in each series. 



VERTEBRAE. 



The vertebral column of Saniwa is represented by 33 fairly well- 

 preserved vertebrae, with fragments of at least two more. Twenty 

 of these may be classed as presacral, the remaining 13 as anterior 

 caudal. The presacral vertebrae as now preserved are in three 

 short series. The first, commencing with the complete atlas, con- 

 bists of the first six of the column (see fig. 13) and a remnant of 

 the centrum of the seventh, all articulated. The next block con- 

 tains a series of four, there probably being one vertebra missing, 

 of which only a fragment of the spine is preserved in the matrix. 

 Although slightly disarranged, as shown in the matrix, plate 3, 

 figure 2, it appears that those preserved were continuous in the 

 series with those shown in plate 2, figure 2. Thus, the presacral 

 series, with the possible exception of one centrum thought to be 

 missing between blocks 1 and 2, form a continuous series from the 

 skull back to the twenty-second vertebra. Since the living Varanus 

 has 29 presacrals, it appears reasonable to suppose that Sanhna had 

 an equal number in the complete series. Thus, there would be onl}'^ 

 seven vertebrae missing from the presacral series — one between the 

 seventh and eighth, the remainder between the twenty-first and the 

 sacrum. The caudal series is now preserved in three separate blocks 

 of matrix, though probably all were originally joined, but the con- 

 tacts have now been lost. There are 13 vertebrae in all of which the 

 larger number, seven (see pi. 3, fig. 1), are so little disassociated as 

 to show they were in series and probably form the anterior part of 

 the tail. 



Atlas. — The atlas is almost perfectly preserved and was but little 

 disturbed from its proper relation with the axis. It consists of the 

 strongly-keeled intercentrum, odontoid, and the two lateral neuro- 

 pophyses, as shown in figure 13. 



The centrum of the atlas (odontoid) is suturally united with the 

 axis, and as in most reptiles its place is taken by the octogenous hypo- 

 physes or intercentrum. It presents a cupped articular surface for the 

 basioccipital and a similar surface behind for the odontoid. The 



» Owen, R. Anatomy of Vertebrates, 1866, vol. 1, p. 404. 



