THE PINEAL BODY 



55 



Eycleshymer, 112 in attempting to explain the unpaired origin 

 of the epiphysis in Amblystoma, maintained that in the phylo- 

 genetic period when the lateral eyes became implicated by the 

 closing of the neural fold, a median eye would arise and thus 

 become most highly functional during the time when the lateral 

 eyes were little, if at all, functional. Cameron, 50 working with 

 the embryos of Rana, Bufo, and Triton, concluded that the 



Fig. 20 Anlage of the epiphyseal complex in a 13 mm. embryo of Salamandra 

 maculata, according to Kupffer, 1893. 



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

 sac; Ch., commissura habenularis ; Po., pineal organ; Sch., pars intercalaris pos- 

 terior; Cp., commissura posterior; M, midbrain. 



epiphysis in amphibia arises as two primary outgrowths from 

 the roof of the forebrain (fig. 21). 



These are placed one on either side of the mesial plane. The 

 outgrowth situated to the right of the middle line disappears at 

 an early age by blending with the left outgrowth. The latter 

 shows most active growth so that the epiphyseal opening becomes 

 situated to the left of the mesial plane. The left outgrowth, 



