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to make, appear ou the surface to bear some slight resemblance to 

 his views. Nothing could be further from being the truth. 



Cunningham, starting from Balfour's well known and now uni- 

 versally accepted belief, that the spinal cord and brain were once an 

 open plate , advocated , as the latest discovery of Vertebrate Morpho- 

 logy, the view that the infundibulum , which is a funnel whose 

 walls consist of nervous matter and nothing else, was the remains 

 of the old mouth, which pierced the brain. One cannot but marvel 

 at the rashness of an hypothesis which annexes without more ado a 

 portion of the nervous system and proclaims it to all the world as 

 the remains of a former passage from the exterior to the stomach 

 of the animal! 



Cunningham overlooks entirely the nature and exceedingly com- 

 plicated development of the processus infundibuli or nervous portion of 

 the hypophysis. Since then as far as I am aware, no further specu- 

 lations have been published as to the whereabouts of the old mouth. 

 And although thanks to Eabl - Rückhard and others we have 

 obtained a certain amount of light on the nature of the pineal gland or 

 epiphysis, the body (hypophysis) at the opposite end of the third ventricle, 

 still remains one of those organs on which all sorts of speculations 

 may be made with impunity. 



And, in truth, we are blessed with all sorts of views as to its 

 meaning. Some of the explanations are in accordance with certain 

 facts of its development. Others, on the contrary, accord with 

 none of the known facts of embryology. 



The nervous part — or as I shall call it, the neural hypophysis 

 — has been considered by Rabl - RticKHARD as a gland secreting 

 cerebrospinal fluid. I must however express a strong opinion that 

 such a glandular function is extremely improbable, for the conversion 

 of a piece of nervous tissue into a gland is absolutely without parallel. 



GoETTE and "Wiedersheim have both regarded the nervous part 

 as remains of a sense organ; against which view a priori little or 

 nothing can be said. The mouth part or oral hypophysis was finally 

 classed by Dohrn as the rudiments of a pair of gill-clefts — a supposition 

 not wholly unsupported by the developmental history. It has also 

 not unnaturally been looked upon as the remnant of a mouth gland. 



Prof. Hubreght made it the basis of his comparisons of Nemer- 

 tead and Vertebrata, and saw in it the remains of the Nemertean 

 proboscis, the Vertebrate notochord being the homologue of the 

 proboscis sheath. These comparisons appear to me to be as little 



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