18 



function of the human vomer. I have before me, at this moment, the skeleton 

 of the Gallaxias, in which the bones of the cranium defy any precise 

 nomenclature. 



The Tuatara, and other neaidy allied species, show a structure in the 

 osteogenesis, or growth of the vertebra?, which does not appear in any other 

 class of the vertebrata. I allude to the supposed power of reproduction of the 

 caudal vertebra? when mutilated. In one of the specimens before the Society, 

 it will be observed that the 34th vertebra is distinctly divided in the middle 

 into an anterior and posterior portion ; and I have observed, in the preparation 

 of the skeleton, that it is at this part that the tail gives way, and not, as might 

 be supposed at a joint. 



Scientific anatomists have, for fifty years and upwards, satisfied them- 

 selves that the cranium is simply a continuation of the vertebral column ; and 

 three to seven have been selected as the probable number of vertebrae thus 

 specialized, more or less, in the various formations. If, however, the very 

 earliest type of a vertebra is to be seen in the caudal vertebra? of the lizard, 

 such difficulties as Dr. Giinther has found in the osteology of the Tuatara, will 

 be more easily understood. 



In a subsequent paper on the Green Lizard, which I hope to have the 

 honour of reading to the Society, I shall allude more fully to this very interesting 

 enquiry. I shall be able to demonstrate, that should the tail suffer mutilation, 

 the injured part will, no doubt, heal over, but will not reproduce distinct 

 vertebra?. I draw this conclusion from the careful examination of the specimen 

 of the Green Lizard, which I deposited in the Museum, in 1862. 



The caudal vertebra?, in most animals, become rudimentary, reduced, in 

 short, to the centrum or body of the bone ; and it was at one time the 

 universal practice to dock the tail and ears in dogs, and even in horses, these 

 mutilations were permanent deformities, and never reproduced. 



As I shall add to this short notice carefully drawn up tables of weights 

 and measurements, etc., I shall not detain the Society with any further minute 

 remarks, with the exception of teeth, in which I find so marked a difference, 

 as to constitute a distinct species from those Dr. Giinther has described. The 

 Tuatara is an acrodont ; the teeth being, as it were, chiselled out of the bone. 



The intermaxillary bones, Dr. Giinther describes, as each supporting a 

 single tooth, " notched, or serrated, at the crown in individuals of middle age ;" 

 and he gives an engraving, not only of the young, but of the middle-aged 

 specimen, where there appears only a single notch, given with two points. In 

 one of the two specimens I have prepared, this description corresponds, but in 

 the other I find each tooth divided by two notches into three pointed cones. 

 Thus, the superior maxillary supports, what appears to me, six teeth on each 

 side, including the intermaxillary, of a similar description, each notched into 

 three points. And as a great difference from Dr. Gunther's description, I find 

 three on the posterior part of the palatal plate of the maxillary bone similarly 

 notched, separated by a deep groove from those on the alveolar edge. The 

 teeth in the lower jaw admit of easier description: on each side of the symphysis, 

 I observe, as in the intermaxillary, a tooth notched into three points ; the 

 outer point slightly diverges, and represents a canine tooth, scarcely visible at 

 fii\st, but increasing in size to a line in length. The system of dentition would 

 therefore stand thus : — 



Upper jaw, alveolar edge . . . 6 + 6 == 12 



,, palatal plate . . . 3 + 3—6 



Complex teeth . . 18 



