xxvi Journal of Comparative Neurology. 



riety in the connections affected with the enveloping mesh-work 

 (which is called " neuroglia" by Rohde) are described. 



The same relations are found in a large number of crustaceans, 

 and an attempt is made to bring these relations into harmony with 

 facts observed by Fritsch, in Lophius and Malopterurus. 



Rohde passes to a comparison with the conditions described by 

 Dohrn. 1 It may be remembered that Dohrn described in sharks, the 

 formation of a sheath about the cell by a process of fusion of nerve 

 cells which form about it. Inasmuch as these could not, as he 

 then thought, be of mesodermic origin, he concluded that the periph- 

 eral layer of the ganglion cell is formed by the fusion of these encap- 

 suling nerve cells. 



Rohde thinks the relations are similar to those he describes in 

 Tethys and Pleurobranchus. Dorhn has since yielded to the over- 

 whelming German influence and denied the ectodermic origin of the 

 sheath cells, but Rohde (and many others) think the original view the 

 correct one. These considerations lead the author to doubt the cellu- 

 lar nature of ganglion cells. 



To the present writer there seems a simpler escape. The periph- 

 eral nucleated sheath of the ganglion cell is formed precisely as the 

 sheath of the fibre is by the subdivision of the primitive neuron and 

 the sheath is but a special form of what is found throughout the nerve. 

 Passing to the invertebrates, we have no right to project conditions of 

 comparatively late origin among vertebrates so far backward. The 

 term neuroglia has no place in describing invertebrate nervous struct- 

 ures, certainly not when applied to the immediate sheath of a fibre or 

 cell. The concentration into a central system is on a much simpler 

 plan than in vertebrates. Even in Amphioxus there is no neuroglia. 

 The structures described as neuroglia are really spongioblast^ and the 

 sheath formation is of necessity greatly accentuated. 



[C. L. H.] 



The Embryology of the Hypophysis of Saurians. 2 



This short paper includes an account of the earlier stages of the 

 pituitary of lizards. In saurians and perhaps all reptiles the hypophy- 

 sis has a three-fold proton (anlag) consisting of a median and two lat- 



1 Mittheil. aus der Zool. Station zu Neapol X, 2, 17. Studie zur Urgeschichte 

 der Wirbelthierkorpers. 



2 Gaupp, E. Ueber die Anlage der Hypophyse bei Saurien. Arch. f. mik. 

 Anat., XLII, 3. 



