‘Those who are acquainted with the habits and food of this species have shown how admirably this apparent defect—viz. the lack of teeth—is adapted to its well-being. Now, if the teeth had existed of the ordinary form and proportions in the maxillary and palatal regions, the egg must have been broken as soon as it was seized, and much of the nutritious contents would have escaped from the lipless mouth; but owing to the almost edentulous state of the jaws, the egg glides along the expanded mouth unbroken, and not until it has reached the gullet, and the closed mouth prevents the escape of any of the nutritious matter, is it exposed to the instruments adapted to its perforation. These instruments consist of the inferior spinous processes,’ etc., already described. ‘They may be readily seen even in very small subjects, in the interior of that tube in which their points are directed backwards. The shell being sawed open longitudinally by these vertebral teeth, the egg is crushed by the contractions of the gullet, and is carried to the stomach, where the shell is no doubt soon dissolved by the acid gastric juice.’ [Illustration: Portion of spine of the Deirodon, from Andrew Smith’s _Zoology of South Africa_. Gular teeth penetrating into the gullet, _ib._ Portion of spine from a skeleton at the museum of the R. C. S., natural size.] The two from Smith’s _Zoology_ must be much magnified; the third, from the skeleton, being the true size, excepting that the ribs are broken short off, some entirely so. The minute processes extend two or more inches. As the learned professor has described the _Deirodon_ (neck-toothed) both under the head of teeth, and also of vertebrated animals, the two accounts are blended, but given _verbatim_ as far as possible. The colour of the _Deirodon_ is of a brightish or yellowish brown, very minutely spotted with white. Such few true teeth as some individuals may possess are extremely small and conical, discovered only towards the angle of the mouth. Dr. Andrew Smith first examined a specimen in 1829, when he found that the gular teeth commence exactly 2-1/4 inches behind the apex of the lower jaw, and penetrate the œsophagal canal through small holes in its tunics, and that each point is armed with enamel. He had observed that the living specimens which he had in captivity always, when feeding, retained the egg stationary about two inches from their head, and while there, used great efforts to crush it. Dissecting a specimen in order to investigate this strange action, he discovered the gular teeth just where the egg had stopped, and which, he felt satisfied, had assisted in fixing it there, and also in breaking the shell when subjected to the muscular action of the surrounding parts. The gular teeth are developed in very young _Deirodons_.