THE PINEAL BODY 



111 



which contain a lumen, but neither have connection with the 

 third ventricle. The cavity of the pineal organ is traversed by 

 protoplasmic processes forming a dense meshwork from wall to 

 wall. Although the pineal organ is highly vascular in Opsanus, 

 it does not conform in structure to any of the known ductless 

 glands, and is, therefore, probably not glandular. There is no 

 pineal nerve, no parietal foramen or fossa, no dorsal sac or 

 paraphysis. 



PV 



PC V 



Fig. 59 Pineal region in an embryo of Opsanus, according to Terry, 1911. 



T.R... lamina terminalis; P., paraphysis; V., velum trans versum ; P.V., post- 

 velar arch (dorsal sac); S., commissura habenularis; E., epiphysis; P.C., pos- 

 terior commissure. 



PHYSOCLYSTI 



21. Gadus morrhua. Baudelot (70). 14 The pineal organ in 

 this species is a long, pear-shaped structure. Cattle" in 1882 

 distinguishes a strand-like proximal portion and an end-vesicle 

 rich in blood vessels. In the latter are round and oval nuclei 

 and round and pear-shaped cells with one or two processes. 



22. Trigla liirundo. Ussow ('82). 40: A short pineal organ 

 with a hollow end-stalk is the characteristic in this species. 

 The end-vesicle is convoluted and reminiscent of the conditions 

 in the hypophysis. The cells bordering upon the lumen are 

 ciliated while the parenchymal cells are probably neuroglia. 



