1 1 4 Mn. F. E. BKDBARD OX THE [Feb. 7, 



fx'ont of tlie sixtli nerves. The arteries of the corpora bigemina 

 are neai-ly symmetrical with each other ; each divides into two 

 branches just before reaching its corpus bigeminum. Of tliese 

 branches the anterior is the smaller. There is nothing specially 

 noteworthy to record concerning the cerebral arteries. 



Goura coronata. — In this bird the two vertebral arteries reach 

 the brain just behind the medulla ; before passing forward 

 they give ofi", as in the case of many mammals (as, for instance, 

 Man), a very delicate anterior spinal artery, thereby contrasting 

 Avith many birds, where the anterior spinal is of as great a 

 calibre as the basilar artery. The vertebrals then run forwarr's 

 separately, and unite to form the basilar artery well behind the 

 origin of the cerebellar arteries. The latter arise much f ui-ther 

 forwards than in the Ostrich (described above, p. 103). Further- 

 more, the branch of this artery which runs backward along the 

 lateral aspect of the medulla diffei's from that of the Ostrich in its 

 relation to the adjacent nerve ; moreover, the main continuation 

 of the artery to the cerebellum has also a diffei^ent relation to 

 adjacent nerves. A final difierence in the arterial system of this 

 region of the bi-ain is that, while in the Ostrich the main branch 

 of the cerebellar artery passes over the flocculus and is distinctly 

 the most important artery of the cerebellum, in Goura the artery 

 which follows the same coiu'se is not derived from the posterior 

 cerebellar, but from an anterior cerebellar arising fi-om the basilar 

 artery further forwards, and which is of the same calibre as the 

 posterior cerebellar. This artery exists in the Ostrich, but is not 

 nearly so large as the posterior cerebellar. The posterior cere- 

 bellars, it should be observed, arise symmetrically from the basilar ; 

 the left anterior cei-ebellar arises in advance of the right anterior 

 cerebellar. As in the Ostrich, the left posterior communicating 

 artery is much the stronger. The anterioily situated cerebral 

 arteries have a curiously asynmietrical and compensative ar- 

 rangement. As in other birds, the carotids curve round and 

 each ends in the ophthalmic artery. The main cerebral arteries 

 are three in number. The first two of these are exactly as in 

 Struthio, lying respectively between the cei-ebrum and the corpus 

 bigeminum and along the Sylvian fissure. The third artery, 

 however, consists of two branches, of which the more important 

 approaches its fellow of the opposite side and runs mesially 

 forward to the olfactory lobes ; the branch running forwards and 

 supplying the under surface of the hemisphere to the side of this 

 is less important. In Struthio the precise reverse is the case. 

 Moreover, this branch, lying to the side of the olfactory branch of 

 the anterior cerebi-al artery, is only well developed on the right 

 side ; it exists on the left side, but is functionally replaced on 

 that side by a branch of the middle cerebral artery. This branch 

 is present on the right side but very small. 



Gymnorhina lencouota. — There are a number of features (see 



