4S 



FREDERICK TILNEY AND LUTHER F. WARREN 



ganglion, a pineal organ consisting of an end- vesicle, stalk and 

 proximal portion, and finally the posterior commissure. 



36 27 3 



39 



Fiji. 1") .Mesial view <if brain reconstruction of 100 mm. Mustelus. X 25. 

 The unshaded area shows the cut surfaces of the reconstruction. According 

 to Tilney, 1915. 



2, chiasmatic process; 3, cerebellum; 4, chiasin; 7, epiphysis; 13, infundibular 

 process; 14, infundibular process, saccular surface; 15, infundibular process, pitui- 

 tary surface; 20, lamina t enniiialis ; 1M, midbrain; 27, mammillary body (post- 

 erior lobe); 32, post-chiasmatic eminence (lobus inferior); 33, post-chiasmatic 

 recess (recess of inferior lobe); 36, post-infundibular evaluation; 3!), paraphysis; 

 40, recess of infundibular process; 41, supra-optic crest; 42, supra-optic recess; 

 44, telenccphalon; 47, velum transversum. 



3. The development of the epiphyseal complex in ganoids 



Kupffer 223 1893 gave the first detailed description of the develop- 

 ment of the epiphyseal complex in Acipenser. The anlage of the 

 organ he describes as a small single evagination which later 

 becomes a stalk with an (Mid-vesicle. Kupffer could find 

 nothing of the anterior or parapineal organ. Owsiannikow 

 ('88) 295 gave a description according to which inthe three- or 

 four-weeks old embryo of Acificnxcr just in front of the pineal 

 organ there appears a small, round or cordifonn structure. 

 llill ls " in 1X1M described a small rudimenl of the anterior or 

 parapineal organ in Aniia calru. In the 10 mm. embryo this 

 bodv was ovoid in form and situated immediately in front and 



