ZOOLOGY AND BOTANY, MICKOSGOPY, ETC. 



29 



tube. If, on the other huiid, the fore-brain is removed without removing 

 the end-organ, the nasal placode, the presence of the latter acts as a 

 stimulus to the regeneration of a new telencephalon through the ingrowth 

 of the optic nerve. The jmlhal region of the telencephalon is regenerated 

 in all cases owing to the stimulus afforded by the forward growth of 

 axones from lower centres in the brain and cord. These ingrowing 



Transverse section through embryo of Aniblystoma one and a 

 half months after the operation, showing the regenerating telen- 

 cephalon as the result of the presence of the nasal placode. 



axones stimulate a mass of neuroblasts at the posterior margin of the 

 interventricular foramen. In three and a half months the new cereljral 

 hemisphere could not be distinguished from its fellow. J. A. T. 



Development of Japanese Giant Salamander. — Dan de Lange, 

 Jun. {TijdscJir. Nederland. Dkrlc. Ver., 1916, 14, 22i-372, 8 pis.). A 

 study of the development of Megalohatraclms maximus during the first 

 eighteen days, especially as regards the anterior region. The cepha- 

 logenesis or protogenesis includes the formation of the head to behind 

 the auditory vesicle and the branchial region, with the exception of 

 the greater part of the protochordal plate. The somatogenesis or deuto- 

 genesis leads to the formation of the anterior half of the trunk, includ- 

 ing the protochordal plate. The urogenesis or tritogenesis, which is not 

 discussed, leads to the formation of the posterior half of the trunk and 

 the tail. Stomodseum, primordium of brain, and the sensory organs of 

 the head are formed in situ by the cephalogenesis ; the protochordal 

 plate is of mixed origin, being in part somatic. The anterior head- 



