112 AETHUR DENDY. 



thus forming an optic cup structurally resembling that of the 

 ordinary paired eye. The conclusion that this cup had been 

 formed in the same way as in the paired eye was irresistible^ 

 but fortunately I refrained from publishing until further 

 evidence was forthcoming, and in the meantime made arrange- 

 ments for securing a supply of Tuatara eggs, with a special 

 view to investigating this point. Thanks to the generous 

 assistance of Mr. P. Henaghan, I have obtained a consider- 

 able number of eggs, from which I have extracted a very good 

 series of embryos. I have recently published a general account 

 of the development of Sphenodou.^ This will be followed 

 by more detailed accounts of the development of special 

 organs, by myself and other zoologists, and towards these the 

 present communication may be considered as a first instal- 

 ment. 



My material was hardened in Kleinenberg's picric acid, 

 followed by different grades of alcohol, and stained with borax 

 carmine in the usual way. The sections were cut by the 

 ordinary paraffin method. 



Owing to the work having been carried out in Christchurch, 

 New Zealand, where, unfortunately, there is no proper 

 scientific library, the difficulties of the investigation have been 

 greatly increased. So much valuable work has been published 

 of late years on the '^epiphysis" and parietal eye of various 

 types, that it was thought undesirable to publish my own 

 observations before having an opportunity of consulting the 

 more important recent papers on the subject by other writers. 

 In order to attain this end, great delay has been caused by the 

 necessity for communicating with England and America, but 

 it is hoped that this delay may be more than compensated for 

 by the increased interest attaching to the work when com- 

 pared with that of other investigators. As a result of this 

 comparison, I find that most of my conclusions have been 

 anticipated by one or other of the numerous writers on the 

 subject. Especially is this true in the case of the admirable 

 work of B^raneck (6, 6) on lizards, and Hill (16,17) on fishes. 



' This vol., p. 1. 



