THE PINEAL BODY 



43 



tion lies in the fact that Studnicka 391 says that the organ is absent 

 in Torpedo marmorata and d'Erchia 109 says that in Torpedo 

 ocellata there is no pineal organ. 



Cr 



Pf 



Ds 



Fig. 10 The cpiphyseal complex in an 86 mm. embryo of Acanthias vulgaris, 

 according to Minot, 1901. 



Hm., hemisphere; Pf., paraphysis, V., velum transversum; Ds., dorsal sac: 

 Ch., commissura habenularis; R., recessus pinealis; Po., pineal organ; Cp.,com- 

 missura posterior; A/., midbrain. 



One of the authors, Tilney ('15), 396 studying the interbrain in 

 Mustelus laevis, illustrated the development of the pineal organ 

 in reconstruction models through a number of stages. The 

 anlage of the epiphyseal complex in Mustelus makes its first 

 appearance in the 9 mm. embryo as a single evagination from the 

 roof-plate. It is a prominent element in this region for some 



