OUTLINES OF THE DEVELOPMENT OF THE TUATAKA. 9 



Tuatara lays its eggs in special holes carefully concealed^ and 

 not as a rule in its ordinary dwelling-holes. This fact doubt- 

 less accounts for the failure of other collectors to find the e^iis. 

 As far as I know Mr. Henaghan is the only collector who has 

 yet obtained the eggs in the natural breeding-places. 



[b) On the Time occupied in Development. 



I quite agree with Mr. Henaghan that the eggs take at least 

 twelve months to develop, — indeed, I think they take rather 

 more, being laid in November of one year and hatched about 

 December of the year following. With a view to establishing 

 this belief I subjoin the following table, in considering which 

 it should be noted that those embryos which have not yet been 

 stained and cleared are only referred approximately to their 

 respective stages, while of course the different stages are con- 

 nected by intermediate ones, so that it is sometimes a mere 

 matter of choice to which stage a particular embryo should be 

 referred. 



It must also be noted that, in the earlier stages of develop- 

 ment at any rate, the sequence of events is not always quite 

 the same. Thus a feature which appears comparatively late 

 in one embryo may appear comparatively early in another; 

 and this inconstancy greatly increases the difficulties of classi- 

 fication. 



The classification is, however, quite sufficiently accurate to 

 establish a most remarkable coincidence between the sequence 

 of dates and that of stages in development. The eggs were 

 numbered consecutively as they came in, and the numbers 

 missing from the following list belong to eggs wliich^ for 

 one reason or another, yielded no embryos. Except Avhere 

 otherwise stated, the date given is that on which the egg was 

 opened. 



