VARANIANS. 265 



transparent, and their fine tubular structure may be discerned 

 with the due microscopic power without cutting the tooth into sUces. 

 I find nine small conical sharp-pointed teeth in the anchylosed inter- 

 maxillaries, the middle azygos incisor being the smallest ; and seven 

 large, compressed, recurved, sharp pointed and trenchant teeth in 

 each maxillary bone. In the lower jaw there are two small conical 

 incisors at the fore-part of each premandibular series, succeeded by 

 nine or ten long compressed teeth corresponding with the maxillaries 

 above. These teeth are more convex on the inner than on the outer 

 side ; their margins are finely crenate. They are separated by mode- 

 rately wide and irregular intervals, in which are contained the suc- 

 cessional teeth, the apices of the largest of these appearing above the 

 outer alveolar ridge. 



These successional teeth are developed at the inner and posterior 

 side of the base of their predecessors : and groups of three and some- 

 times four teeth, placed one a little behind the other and successively 

 diminishing in size from the tooth in place to its third successor, are 

 arranged in the alveolar groove, as shown in PL 63 a, fig. 9. The 

 old teeth are not so much damaged by the growth of their successors 

 as in other Saurians ; and the young teeth are at no period inclosed 

 in a cavity in those which they succeed. 



In the great crocodilian Monitor {Varanus crocodilinus, PI. 68, 

 fig. 3), the large fixed compressed teeth, of which there may be about 

 seven in each upper maxillary bone and six in each premandibular, 

 are anchylosed by the whole of their base and by an oblique surface 

 leading upwards on the outer side of the tooth to a slight depression 

 on the oblique alveolar surface, as in the Var. striatus, PI. 63 a, 

 fig. 8 a. The base of the tooth is finely striated, the lines being pro- 

 duced by inflected folds of the external cement, as in the Ichthyosaur 

 and Labyrinthodon, but being short and straight as in those of the 

 former genus. The alveolar channel or groove has scarcely any 

 depth ; but the anchylosed base of the tooth is applied to an oblique 

 surface, terminating in a sharp edge, from which the outer side of 

 the free crown of the tooth is directly continued. The great Varanus, 

 like the variegated species, manifests its affinity to the Crocodihans 

 in the number of successive teeth which are in progress of growth to 



