250 Transactions. — Zoology. 



concerning the breeding habits of the Tuatara, which were 

 previously ahuost entirely unknown.* The eggs w'ere sent to 

 my laboratory packed in damp earth or sand, in tin cans, and 

 wlien sent only a few at a time were found to travel very well. 

 Indeed, later on, after the discovery of the hibernation of the 

 embryo within the egg, my wife even took eggs to England 

 with the living embryos in them, and they arrived safely at 

 their destination. In the early stages of development, how- 

 ever, it is not very easy to prevent the eggs from either shrivel- 

 ling up or going mouldy. Owing to these satisfactory ar- 

 rangements it became unnecessary for me to visit Stephens 

 Island personally, as I had thought of doing, and I was able 

 to prepare and examine the embryos with all the conveniences 

 afforded by my laboratory at the Canterbury College. 



It appears that the failure of earlier collectors to obtain 

 the eggs of the Tuatara was due to absence of information as 

 to the breeding habits. It is well known that the adult 

 animals live in holes, which are frequented also by sea-birds, 

 and, indeed, the young of the birds serve them for food. The 

 Tuataras, however, do not, as a rule, lay their own eggs in 

 these holes, as was naturally enough supposed. On the other 

 hand, Mr. Henaghan found that they make special holes for 

 the reception of their eggs. In each of these " nests " from 

 ten to fifteen eggs are laid, apparently by a single female, and 

 the hole is then carefully filled in and concealed with grass or 

 leaves. 



The eggs are laid on Stephens Island during the month of 

 November, and it is a very remarkable fact that they do not 

 hatch until about midsummer of the year following. The 

 earlier stages of the development are passed through much 

 more rapidly than the later ones, and about the month of 

 March, having already reached a very advanced stage, the 

 development of the embryo is almost suspended for the winter 

 months, being resumed again in the following sprmg. This 

 hibernation of the embryo within the egg has been observed in 

 only one other vertebrate animal, and that is the common 

 European tortoise.! Certain other developmental features 

 also indicate a close relationship between the Tuatara and 

 the Chelonians (turtles and tortoises). 



The eggs, when newly laid, are usually rather more than 

 an inch long, and of broadly oval shape. They are almost 

 entirely filled with yellow yolk, and contain very little albu- 

 men, or " white." As the time of hatching approaches the 



* See, however, Professor Thomas's paper, "Preliminary Note on the 

 Development of the Tuatara [Sphenodoti inuictatum)." — (" Proceedings of 

 the Rojal Society of London," vol. 48; and " New Zealand Journal of 

 Science," vol. 1, 1891.) 



t Emis orbicularis. Vide Boulenger ("Nature," 27th October, 1898). 



