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 nearly allied species, show a structure in the osteogenesis, or growth of the vertebræ, which does not appear in any other class of the vertebrata. I allude to the supposed power of reproduction of the caudal vertebræ 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 themselves that the cranium is simply a continuation of the vertebral column; and three to seven have been selected as the probable number of vertebræ 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 vertebræ of the lizard, such difficulties as Dr. Günther 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 vertebræ. 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 vertebræ, 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. Günther has described. The Tuatara is an acrodont; the teeth being, as it were, chiselled out of the bone.

The intermaxillary bones, Dr. Günther 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 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. Günther'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 first, but increasing in size to a line in length. The system of dentition would therefore stand thus:—

Remarks.—The hœmapophyses (V-shaped bones) I observe, throughout the whole spinal column, connected with the inter-articular cartilages; in neck, rudimentary (but formed of three points of ossification), disappearing along the