THE PINEAL BODY 



35 



The parietal eye which occurs in many forms of Lacertilia is, 

 on the other hand, entirely absent in Ophidians, Chelonians, and 

 Crocodilians. In all reptiles, with the exception of Lacertilia, 

 the epiphyseal complex is so rudimentary that only the proximal 

 portion of the pineal organ remains. Indeed, in Crocodilia even 

 this is said to be absent. 



rrrnn 



Ls. 



Fig. 6 Schematization of the pineal region in Ophidia, according to Studnicka, 

 1905. 



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

 sac; Ch., commissura habenularis; Ep., proximal portion of pineal organ (epiphy- 

 sis); Cp., posterior commissure. 



Burckhardt 45 in 1893 gave the first description of the pineal 

 region n the brain of Lacerta. He described a thin and flat 

 lamina supraneuroporica above which arose, to a considerable 

 height, a simple tubular paraphysis. In adult animals, as a 

 rule, this structure has the form of a thin-walled sac lined by 

 cuboidal ependymal cells. The paraphysis at first is without 

 vascularization, but later, by the ingrowth of blood vessels, it 

 becomes highly plexiform in character; yet in no instance is it 

 comparable to the vascularity observed in Amphibians. The 

 distal extremity of the paraphysis is flexed dorsally and often 



