808 



which usually limits the pars medialis laterally, is not conspicuous. 

 Ccf. fig. I with fig. 535 — 537 Ariëns Kappers, 1291. Vide also Owen, 

 1872, p. 382). 



Another important feature of the brain is the presence of two 

 large olfactory lobes (fig. II). These project for a short distance 

 beyond the anterior extremity of the fore-brain (tig. I and fig. 11). 

 Extending posteriorly they receive a very wide attachment to the 

 ventral aspect of the frontal region of their respective hemispheres 

 (fig. II). In marked contrast with this unique degree of development 

 amongst Aves of the olfactory lobes, the visual apparatus is very 

 poorly developed compared with a typical avian brain, as is 

 indicated by the smallness of the optic nerves, chiasma, tracts and 

 lobes (fig. II). This enhanced importance of the smell centres and 

 associated reduction in the importance of the visual connections, 

 combined with the presence of an apparently simpler hemisphere 

 than is usually the case in Aves, suggest the conclusion that the 

 brain of the kiwi is a comparatively simple and primitive type of 

 avian brain, (cf. Owen 1841, p. 287). For these reasons Dr. C. U. 

 Ariëns Kappers kindly suggested that 1 should undertake the 

 investigation of this brain. It is a pleasure to express to him my 

 great indebtedness on this account, and because of the assistance 

 he afforded me in carrying out the comparative investigation 

 necessary to elucidate the somewhat unusual features of the specimen. 



II. Technique. 



The material consists of a transverse series of sections of a single 

 brain. Alternate sections were stained by the van Gieson method; 

 the series remaining was treated by the Weigert-Pal-para-carmine 

 method described by Ariëns Kappers and Ketjen (1911). unfortunately 

 the specimen was in alcohol when received by Professor Elliot Smith 

 from the Zoological Gardens, London, who kindly transmitted it to 

 the Central Institute of Brain Research, Amsterdam, aftei- transference 

 to formalin. The brain was evidently in a bad state of preservation 

 before being hardened. In consequence, the condition of the sections 

 is not good and a final analysis of the cell masses and their fibre 

 connexions is not possible. However many features are so clearly 

 defined that a description of them may be entered upon with 

 confidence. To control the topographical description of the various 

 parts a wax plate-ceresine reconstruction twelve and a half times 

 the size of the original, was prepared, (cf. Ahiëns Kappers 1915). 



