66 JOURNAL OF SCIENCE. 



cases, not be free from doubt, unless tbe specks be detached and 

 specially tested. This is on account of the smallness of the specks, and 

 their frequent association with, and general resemblance in colour to, 

 grains of pyrite, which may therefore be easily mistaken for it. The 

 simplest test in the case of detached specks is by application of the 

 magnet, which energetically attracts the Awaruite specks, but leaves 

 those of pyrite unaffected. The malleability of the specks affords 

 another proof of their identity. 



ON THE HISTORY OF THE KIWI * 



BY PROF. T. JBFFERY PARKER, F.E.S. 



The development of the brain presents some points of interest- 

 The brain of birds closely resembles that of reptiles, differing 

 chiefly in the fact that owing to the increased size of the central 

 hemispheres and cerebellum the optic lobes which in reptiles lie in 

 contact with one another on the upper surface of the brain, are pushed 

 outwards and come to lie, widely separated from each other, one on 

 each side. 



In the embryo of the kiwi, as in that of other birds, the brain is 

 at one stage precisely like that of a reptile, having a pair of large 

 optic lobes closely applied to one another, on the upper surface. As 

 development goes on the optic lobes gradually separate from one 

 another and take up a position on the sides of the brain, the 

 cerebellum and cerebrum at the same time uniting between them. 

 At this stage, therefore, the brain is precisely like that of an 

 ordinary typical bird. Later on the eye undergoes a relative 

 dimunition in size, the optic lobes also become smaller in proportion 

 to the remaining part of the organ, and being overgrown by the 

 cerebrum come to lie in the adult on the under surface of the brain, 

 where they form a pair of insignificant elevations. It may also be 

 mentioned that, apart from the optic lobes, the brain of Apteryx is by 

 no means of a low type ; the cerebral hemispheres are, in fact, as 

 large in proportion to the brain as in a passerine bird. 



So far, it will be seen, the study of the development of the kiwi 

 certainly tends to show that its relation to ordinary or carinate birds 

 is closer than would be expected from a study of the adult anatomy. 

 There is, however, one very striking point of divergence. 



The " tail " of a carinate bird consists of a variable number of 

 tail-quills, covered above and below by smaller feathers or tail-coverts, 

 and arranged in a half-circle round the true tail of the bird — the 

 small conical projection known as the " parson's nose " or uropygium. 

 In order to support these feathers the last few vertebra? are united 

 into a strong conical mass or " ploughshare bone." In the kiwi 

 there is never any trace of tail-quills, the uropygium being from its 

 first formation to adult life a naked stump quite devoid of feathers. 



Continued rom page 9. 



