300 Natural History Bulletin. 



cate that at one time the oral cavity and the brain may have 

 been more intimately connected than at present." 



In a recent work on Embryolog}'^ this sentence occurs: 

 " The pituitary body arises in most Vertebrates as a tubular 

 invagination of the roof of the mouth (stomodeeum) approach- 

 ing the infundibulum." In Minot's Human Embr3^ology2 we 

 find the following: "The hypophysis cerebri, Rathke's pocket 

 or pituitary body [Hirnanhang^ is a structure of very problem- 

 atical significance, which has been much studied and specu- 

 lated upon by embryologists. It arises in all Vertebrates as 

 an evagination of the ectoderm near the dorsal border of the 

 oral plate, but is separated from the plate by a fold of the 

 ectoderm." Again, oa page 574, we find,— "The infundibu- 

 lum also contributes to the production of the adult hypophysis 

 of mammals, although in lower Vertebrates it persists as an 

 integral portion of the brain, and is differentiated into gangli- 

 onic tissue." 



But on page 687 he says, under the head of Infundibulum, 

 — "In rabbit embryos of 12-16 mm. and in human embryos 

 of five weeks there is found developing a small cylindrical 

 outgrowth of the brain, which is known as the processus 

 infundihuU. The outgrowth takes place in the median fine 

 immediately in front of the tuber cinereum and behind the 

 optic chiasma. It very soon comes in contact with the hvpo- 

 physal outgrowth of the mouth, and is ultimately transformed 

 into the posterior lobe of the pituitary body as already 

 described." This is the nearest approach to tlie exact use 

 of terms that I have found in the literature bearing- on this 

 point. 



Arranging these various opinions in order, we find that 

 the following ideas have prevailed with regard to the region 

 under discussion. 



' An Introduction to the Study of Embr)ologv, by A. C. Haddon. P. Blak- 

 iston, Son & Co., Philadelphia. 1889. p. no. 



* Human Embryology, by C. S. Minot. William Wood <fc Co., New York. 

 iSq2. p. 571. 



