The Hon. W. Rothschild on Apteryx Haastii. 43 



the canal in question is somewhat obscured, owing to the fact 

 that a large venous vessel lies near it. 



The Brain and the Ganglia. 



In a provisional communication, which is not accompanied 

 by figures, very little can be said as to these organs. Some 

 days before the embryos are hatched the brain already 

 possesses several divisions. During the formation of tlie 

 optic vesicles the anterior wall of the fore brain is represented 

 by a very thin lamella. The hemispheres and the olfactory 

 lobes are developed afterwards. The hypophysis originates 

 from the ectoblast, while in almost all other animals it is 

 formed from the cells of the endoblast. 



As to the epiphysis, I have made certain statements in the 

 paper which has recently appeared on the third eye of the 

 Lampreys. All ganglia (of the head, as also of the trunk) are 

 produced from the cells of the ectoderm. The cerebral ganglia 

 appear to arise at a very early stage. They subsequently 

 separate from the epidermis, and appear to be related to the 

 mesoblast. In embryos of from 2 to 3 millim. in length, 

 however, we still find them in connexion with tlie integument. 

 The spinal ganglia arise later on, and not above the spinal 

 cord, but to the side of it. I have observed epithelial cells 

 extending inwards from the skin like a plug between tlie 

 protovertebrge. At a subsequent period they lay near the 

 spinal cord, already sc])arated from the skin, and forming 

 a roundish independent group. From the spinal cord there 

 proceeded a short fascicle of nerve-fibres — that is, a root — in 

 the direction of the ganglion-cells. A junction between them 

 was n/)t as yet established. 



]n concluding this short communication I cannot refrain 

 from mentioning that the description and figures by A. Dohrn 

 of the cerebral ganglia (as, for instance, those of the tri- 

 geminus, ophthalmicus, facialis, vagus, and other nerves) are 

 in the highest degree true to nature. I possess a large series 

 of preparations, which show precisely the same picture as his 

 figs. 1, 2, & 4 of pi. 10, and especially fig. 6 of pi. 11 

 (Bd. viii. Heft 2). 



VI. — Notes on Apteryx Haastii. 

 By Walter Rothschild. 



Mr. Forbes has expressed it as his opinion that Apteryx 

 Uaasiiih a natural hybrid between A.australis and A. Owenii. 

 I have paid much attention to this question as well as to the 

 study of this genus generally, having had during the last four 



