120 



FREDERICK T1LXHV 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 epiphy-ea! structures whatsoever in crocodilia offers much 

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

 vest Ration. 



The pineal on/an in saurians and prosaurians (form Sphenodon] 

 seldom presents all three of the several parts usually observed 

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



-Hm 



. (>'2 'I'li<' cpiphyscal complex in Sphcnuxlon according fo Spencer, 1SS<>. 

 I'n., p:ii';ipinc:il organ icnd-vrsicio i ; /'/., parapliysis ; I)*., dorsal sac; I'.'/i., 

 proximal portion of pineal organ; .I/., 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-' 1 '-' in IX 1 .)',) showed that not only 

 may the eiid-s.-'c be absent, but the rest of the parapineal organ 

 may pivM-nt itself in a degenerative condition. This is true in 



