233 Zoological Society. 



How hazardous it is to judge of the size of a bird by that of its 

 egg would appear, Prof. Owen observed, b)^ the remarks which he 

 should next proceed to offer on the eggs of the Apteryx. Of these 

 the Professor exhibited one entire specimen, and a nearly fully incu- 

 bated chick from a second egg, both of which had been most liberally 

 transmitted to him by the llev. Wm. Cotton, M.A., from the North 

 Island of New Zealand. 



Had it not been for the demonstration afforded by the chick itself, 

 it might well have been doubted whether so small a bird could have 

 excluded so large an egg. The following are the dimensions of the 



egg:— 



Egg of Apteryx, 



ft. in. lin. 



Greatest longitudinal circumference 1 9 



Greatest transverse circumference 10 



Length 4 10 



Breadth 3 2 



The egg presents the usual long oval form, the colour a dull d'rty 

 greyish white ; but this is partly due to grease stains from the de 

 composition of an incompletely hatched chick, with its yolk, within. 

 Viewed under a moderately magnifying power the surface presents 

 a very fine fibrous, or spicular charactei ; the raised lines, like spiculae, 

 crossing in opposite directions, with air-pores scattered here and there 

 and barely perceptible to the naked eye. The shell is not more than 

 ■i-th of a line in thickness. Supposing, as is most probable, from the 

 size of the bones of the ^^pyornis, that it did not exceed the Binor- 

 nis giganteus in size, the egg of the JSpyornis is smaller in propor- 

 tion to the bird itself than the egg of the Apteryx is in proportion to 

 that bird. 



The embryo Apteryx, which had been removed from its shell, had 

 nearly reached the term of its incubation, the yolk-bag being reduced 

 to a hernia-like appendage of an inch in length and half an inch in 

 breadth, protruding about two lines in advance of the cloma, and 

 covered by a continuation of the ordinary integument of the abdomen : 

 the free end of the hernia was open, and exposed the ruptured ends 

 of the allantoic vessels. 



The whole body was clothed by down-fascicles, presenting the ap- 

 pearance of moderately thick cylindrical hairs, \\ inch in length, 

 with a smooth, unbroken exterior, gradually tapering to a fine point. 

 This smooth surface is due to an extremely delicate capsule, which 

 when torn open exposes the down-tuft, consisting of a central stem 

 with slender smooth barbs from 3 to 5 lines in length, diverging 

 loosely from each side of the stem. 



in. lin. 

 Length of the body from the base of the beak to 



the tail 4 



Length of the beak 1 7 



Length of the leg from the knee-joint 4 3 



Length of the freely projecting part of the fore- 

 limb from the elbow-joint 6 



