120 



FREDERICK TILNEY AND LUTHER F. WARREN" 



alterations in the loss of several of its parts as compared with the 

 lower forms already considered. Finally the reported absence 

 of any epiphyseal structures whatsoever in crocodilia offers much 

 room for speculation or, perhaps, serves as an incentive to rein- 

 vestigation. 



The pineal organ in saurians and prosaurians (form Sphenodori) 

 seldom presents all three of the several parts usually observed 

 in the pineal organ, and it is not possible to identify an end- 



-Hm 



Fig. 62 The epiphyseal complex in Sphenodon according to Spencer, 1886. 

 Pa., parapineal organ (end- vesicle) ; Pf., paraphysis; Ds., dorsal sac; Ep., 

 tproximal portion of pineal organ; M., midbrain. 



vesicle, a stalk, or a proximal portion. Often the end- vesicle is 

 .absent, and in no instance does it assume the proportions or 

 the characteristics of a visual organ. The stalk is usually 

 hollow, but contains no nerve fibers, and in the instances in which 

 the end- vesicle is absent, the stalk is drawn out into a tapering 

 process or end- tube. Melchers 269 in 1899 showed that not only 

 may the end-sac be absent, but the rest of the parapineal organ 

 :may present itself in a degenerative condition. This is true in 



