Literary Notices. Ivii 



field. It is with no small satisfaction that we observe that Professor 

 His still insists upon the sufficiency of the views which he has long 

 advocated, and which were independently reached by the writer and 

 have been used in this Journal, particularly regarding the morpho- 

 logical front of the vertebrate head. The simplest fundamental con- 

 dition of the arched neuraxis is presented by very early stages of 

 Petromyzon, frog, Pristiurus, etc. Fig. 4 of the paper illustrates a 

 torpedo embryo, in which the neuroporus is wide open and occupies 

 the place of the future terma. The dorsal limit of the latter in man 

 coincides with the ori i\\\ of the plexus, the ventral limit being the 

 recessus opticus. The recessus infundibuli and recessus opticus form 

 the fundus basilaris, which is funnel-shaped, but divided by the 

 chiasm The problem as to the point which should be selected as the 

 front of the brain will be answered in accordance with one's concep- 

 tion of the position of the brain axis. Professor His choses the base 

 of the tube and accordingly the front of the brain is for him in the 

 middle of the basilar ridge; i. e. , in the infundibulum. If the axis 

 be taken in the middle of the tube its termination will fall in the re- 

 gion of the recessus opticus — if in the roof of the tube the end would 

 coincide with the summit of the terma or velum transversum. 



It seems to us that nothing in the recent writings of Professor 

 Kupffer or Van Wijhe undermines the positions taken. Mr. Bawden 

 and the writer have elsewhere brought forward fresh evidence in favor 

 of the above view. For example, we have shown that, in the duck, 

 the chorda dorsalis terminates in a special pharyngeal sac which lies 

 caudad of the pharyngeal velum. It is found that in the subsequent de- 

 velopment the sac atrophies and converges to unite with the hypophysis 

 rudiment before the stalk of the latter entirely disappears. The actual 

 communication of the chordal tube with the pharynx seems to us 

 strong evidence that the front ot the head cannot be far distant. 



To return to the paper before us, the eminentia interpeduncularis 

 or locus of the ganglion of that name is regarded with Burckhardt as 

 the limit of the mesencephalon. The cephalic diverticle of the diges- 

 tive epithelium or SeesseFs pouch, with the corresponding diverticle of 

 the ectodermal invagination or Rathke's pouch lie cephalad of the 

 cinereum at first, but reteat to a point caudad of it. The hypophy- 

 sis is a diverticle of the latter [and we may add, the pharyngeal pouch 

 is a similar diverticle of the former.] 



One result of the above consideration on which we have also in- 

 sisted is the inappropriateness of attempting to distinguish a prse- 

 chordal from an epichordal segment of the brain. 



