PROFESSOR OWEN ON THE GENUS NESTOR. 371 



between the postfrontals and paroccipitals ; in the proportions of the postfrontal and 

 mastoid ; in the orbits scarcely at all impressing the under and fore-part of the cranium ; 

 and in the relative extent of the temporal fossfe, although the lower boundary of these is 

 not developed into a vertical ridge as in Porphyria. But, on the other hand, Brachypteryx 

 more resembles Notornis in the relative breadth of the occipital region than Porphyria 

 does. In the comparatively small iJrac/i?/p<er7/a; and Porphyria, in which, as in all small 

 birds, the cerebral hemispheres, as requiring a certain bulk for their functions, do not 

 decrease in proportion to the general bulk of the body', the upper surface of the cranium 

 is raised by the hemispheres beneath into a smooth convexity. The chief characters 

 of the skull by which Porphyria and Brachypteryx resemble Notornis, are participated in 

 by the European and African Rallida ; but in the forms and proportions of the upper 

 and lower bones of the beak, the Porphyria of all existing birds makes the nearest ap- 

 proach to Notornis. 



Upper mandible of Nestor. 



The fourth genus of bird indicated by portions of the skull in Mr. Walter Mantell's 

 collection is plainly referable to the family of Parrots {Psittacidee) , and particularly 

 to the genus Nestor. The bony portion of the upper beak (PL LIII. figs. 11, 12, 13), — 

 the only part of the skull preserved, — by its deep, subcompressed, curved and pointed 



' "The brain in birds, as in reptiles, bears a proportion rather to tlic heart than to the whole body. In the 

 Humming-bird it is as 1 to 12 ; in the Ostrich as 1 to 3000 : the medium or average proportions of the brain to 

 the body of birds, is computed by M. Leuret to be as 1 to 212. 



" The hemispheres consist chiefly, as Cuvier has stated, of a mass of cerebral matter, which, by its intermix- 

 ture of grey and white matter, resembles the corpus striatum. 



" The cerebrum has been thought, from its large proportionate size in some of the lightest and most diminu- 

 tive of the feathered tribe, to be better developed in them than in the Elephant, the Orang, or even in Man him- 

 self. But the supraventricular mass of cerebral matter, which constitutes the actual characteristic superiority of 

 cerebral organization in the brain of Mammalia, is in birds not better developed than in reptiles." 



" The lateral ventricles are covered laterally, superiorly, posteriorly by the thinnest film of medullary matter. 



" Space seems to be almost or altogether denied for the location of the phrenological organs, to which the 

 very striking and various psychological manifestations and instincts of the Bird might be assigned." — Report of 

 Prof. Owen's Hunterian Lectures on the Nervous System, ' Medical Times,' October 29th, \iii2. 



" Thus, it is well known that the general statement, that the brain of Man is larger in proportion to the entire 

 weight of his body, has been disproved by the fact that a higher proportion is presented by several small birds 

 and rodents. But if the statement had been made that the cerebrum of Man is heavier in proportion to the 

 weight of his body than that of any other animal, we apprehend that it would have been strictly correct. For 

 the encephalon of birds is still made up chiefly of the chain of ganglia we have described, which attains, we 

 believe, its highest development relatively to the weight of the body in that class. On turning aside the cere- 

 bral hemispheres (which do not yet cover in the optic lobes) we find that they really form but a thin lamina, 

 beneath which lies a series of large protuberances, which the study of their connections at once discovers to 

 consist of the corpora striata, thalami optici and optic ganglia. If these were weighed, exclusively of the 

 cerebrum proper and cerebellum, we are assured that they would bear a larger proportion to the whole body 

 of the smaller birds than they would in any other class." — Carpenter's Article XIII. of the ' British and 

 Foreign Medical Review,' IS^e, p. 501. 



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