﻿166 Transactions. — Zoology. 



Art. XX. — On the Microscopical Structure of the Egg-shell of the Moa. 

 By Captain F. W. Hutton, F.G.S. 



(With Illustrations.) 



[Read before the Wellington PhilosopJiical Society, 26th August, 1871.] 



Having been kindly supplied by Dr. Hector with some broken fragments of 

 the Moa's egg, I have now the honour to lay before the Society the results of 

 a microscopical examination which I have made of them ; I must, however, 

 first observe that I have been informed that the structure of the Moa's egg was 

 described many years ago, but, as I cannot find any trace of that description, I 

 hope I shall escape the accusation of making you listen to a repetition of well 

 known facts. 



About four years ago Dr. Blasius published an extensive and detailed 

 account of the structure of the shell of birds' eggs. This account I have not 

 seen, but I am aware that he arrived at the conclusion that the microscopic 

 differences are neither constant nor reliable, and cannot be used for purposes of 

 classification. There is, however, one constant feature that distinguishes the 

 eggs of the Struthious birds from the rest of the class, or the Cai-inate birds. 

 This is, that in the eggs of the Struthious birds the carbonate of lime shows a 

 prismatic structure, while in the eggs of the Carinate birds the prismatic 

 structure is absent. 



T believe that I have examined the egg-shell of more than one species of 

 Moa, but I find the structure to be fundamentally the same in all, and that 

 the differences in different portions of the same specimen are quite as great as 

 in any two difi'erent specimens. The shell, when not abraded, is of a pale 

 yellow colour, smooth, and ii'regularly pitted on the outside with dots and 

 linear markings, sometimes 0-08 of an inch in length. (PI. IX., Fig. 1). On 

 sooie fragments the markings were all straight, in others they were nearly all 

 curved, while in others again both straight and curved markings occurred 

 together. Round dots were on all the specimens. In appearance they ai-e 

 more like the egg of the South American Hhea than any other that I know. 

 The specific gravity I foimd to be 2-714. On dissolving in dilute hydrochloric 

 acid no residue was left. The shell is about 0-07 of an inch in thickness, and 

 is divided into two layers, each presenting a different stracture (Fig. 2). 



The outer layer (Fig. 2 a) forms about two thirds of the whole thickness, and 

 is composed of a large number of thin laminae, arranged parallel to the surface 

 of the egg. Each of these laminse appears to be void of structure when viewed 

 under a power of 400 diameters, being made up of numerous points variously 

 aggregated together into clouds (Fig. 3), very similar in appearance to mixcilage. 



