8 TROF. G. 15. JIOWES AND MK. 11. 11. SWINNERTON ON THE 



The tracings, as cut out, were laid flat in superposition, adhesion being eff"ectcd by 

 carefully running a lioated wire along their edges. The use of colour was deemed 

 desirable, but a ])ossil)i]ity of error seemed likely to arise were the models coloured 

 after completion. Tliis, however, was obviated by colouring the tracings before they 

 were cut out; and a perfectly reliable result was obtained by the use of ordinary 

 oil-iniint dissolved in xylol, to secure rapidity in drying. In plates thus treated, the 

 melting together of their edges ensured the diffusion of the colour necessary to 

 produce the final realistic result. 



4. Observations on the Egg, on Hatching, and on the Hatched Young. 



During the period of Prof. Uendy's activity, both as collector and investigator, which 

 led to the publication of his two pioneer memoirs on the Development of Sphenodon 

 (Dendy, 98'', 98'^), there arrived in New Zealand two German naturalists — one Dr. H. 

 Schauinsland, of the Bremen Museum, the other Prof. G. Thilenius, of Strasburg ; one, 

 if not both, of them sent out under the auspices of the Berlin Academy. Each has 

 since published preliminary reports upon his investigations [cf. List, p. 74), without, 

 however, in any way alluding to Dendy's work ; and this is the more regrettable, since 

 in matters of small detail their statements both difl'er from and supplement his — while 

 it is the more unaccountable, since one of them was permitted by the New Zealand 

 Government to explore the same island as Dendy, with the aid of the very collector he 

 had employed. Since neither of them has written upon the skeleton, we omit further 

 reference to their work, except so far as it concerns the newly-hatched young. Dendy, 

 in defining his Stage S, inclined (99\ p. 59) to the belief that the yolk is still pendant 

 at hatching, and was unable to decide definitely upon his surmise (pp. 79-80) that the 

 olfactory cellular-plugs which he discovered are at that period " removed." Schauins- 

 land, on the contrary, both figures the yolk and describes the nasal plug as absorbed 

 shortly before hatching (98°. p. 312), and there can be no doubt he is correct. It is 

 but just, however, to Prof. Dendy to state that in a letter to one of us, antedating the 

 publication of Schauinsland's notes, he had corrected his former statements [cf. letter 

 to ' Nature,' vol. lix. p. 340), having discovered that the embryos which had led him to 

 believe that both yolk and plug might be present on leaving the egg had been 

 prematurely hatched. 



Concerning the newly-hatched young, he further points out that the pineal eye is 

 " plainly indicated by an irregular scale, surrounded by eight or nine others, radially 

 arranged, and all much larger than the surrounding granules," an observation which 

 we can confirm. And to this we would add that the supra-pineal area of the skin of 

 the head is at hatching transparent and pigmentlcss, and that it remained in that 

 condition throughout the four months our young ones were alive. 



Before passing to the main subject of this Memoir, we desire to record some 

 observations pertinent to those communicated by us, in conjunction with Dr. Dendy, 



