THE PINEAL BODY 



51 



Still later many small diverticula develop in the walls of the 

 end-vesicle which become unusually large. A feature of the 

 description of the development given by these authors is the 

 absence of any anterior or parapineal element in the epiphyseal 

 complex, for this organ, according to their observations, does 



M 



Cp R Ch Ds 



Pf Ls 



Rn 



Fig. 18 The epiphyseal complex in a four months old embryo of Acipenser 

 sturio, according to Kupffer, 1893. 



Ls., lamina terminalis; P/., paraphysis; V., velum transversum; Ds., dorsal 

 sac; Ch., commissura habenularis; R., recessus pinealis and pineal organ; Cp., 

 commissura posterior; M., midbrain. 



not even make its appearance in anlage. Holt ('91) 189 described 

 the development of the epiphyseal complex in Clupea harengus. 

 In this form the organ began as a solid sprout and later devel- 

 oped a lumen. The walls of the end-vesicle were eventually 

 thrown into a number of diverticula. Mclntosh and Prince 254 

 in 1891 confirmed the findings of Hoffmann and Rabl-Rtickhard. 

 Hill's 179 observation in 1891 is of unusual importance, for this 

 observer, working upon Coregonus albus and later 180 in 1894 on 

 Salmo catostomus teres, Stizosthetium vitreum, and Liponus 

 callidus, found what he took to be the anlage of the anterior or 

 parapineal element just as he had found this element in Amia 



