l'J_ FKKDKKICK TII.NKV AM) LI THKK F. WAKKKX 



marked tract us pinealis, nevertheless in a certain number of 

 instance- a nerve tract may be observed connecting the pineal 

 organ with the roof of the interbrain. 



/// ()/>hi(/iti the pineal organ is rudimentary. Only the prox- 

 imal portion persists in the snakes. This, however, has under- 

 gone considerable modificat ion from the proximal portion already 

 encountered in the lower vertebrates. In the true snakes it is 

 a compact, highly vascular structure to which the term epiphysis 

 or corpus pineale may, in the strict sense, be applied. Hoff- 



Cor 



Fig. <>:{ The opiplivx'.-il complex in Annuls frntfilis, according to 

 L891. 



/'.".. p:ir:i|)iiii-:il nr^.-in; l'l\>.. pnixiiiuil port inn of pineal or.nan. 



jnann ls ' ; in isxii showed that tlu^ corpus pineale in ophidia begins 

 in its development as a simple evagination from the intcrbrain 

 roof. How it a.ttains its later complicated, compact form is not 

 yet exactly known. Xo doubt the solid epiphysis due to the 

 proliferation of the wall of the anlage causes the obliteration of 

 the lumen of the original evagination. A paraphysis develops 

 <-;irly in ophidians and has in its inception the same general form 

 as t he epiphysis. The pineal region in the adult consists, t here- 

 fore. of ; p.-iraphysis which is a thick-walled structure associated 

 with i he chorioid plexus, a velum I ransversiim and a, dorsal sac 



