L'L' FREDERICK TILNKV AM) LUTHER F. WARREN 



with the pineal organ, the so-called pineal nerve, ends in the 

 po-terior commissure, while the p;ir;ii)ineal nerve has its termi- 

 nation ni the commissura habenularis. 



Probably the first observation upon this region in the cyclo- 

 stomes was made by Serres 3 -"' 3 in 1S25. Other contributions fol- 

 lowed by Schlemm and d'Alton 347f in 1838. Johannas Miiller-" 

 in ls:;s and Siebold and Stannius 3:>:> in 1854 added their studies 

 of this region. Mayer- 1 '-" 1 in 1S(>4 mentioned the occurrence of 



EpuL Cor 



Po 



Schd 



. 1 Schematization <if pincul region in Cyclostomes, iicconliujr to Stud- 

 nicka, l ( .tii">. 



L., lamina terminalia; /'/. p.-napliysis; /'/., para pineal oi^an :/'., pineal or.iiau ; 



Ef a., habenular ganglion; Th., p.-u-apincal aervejCA., commissura lialicnulari^ ; // . 

 recessus pincalis; ('/>., oonnnis.-iua posterior; ., Xfiin., norvus pim-alis. 



m.-iny calcium corpuscles in and about the pineal origin. Wie- 

 dcrsheini' 1 -- in 1880 spoke of the epiphysis as a, small, saccular 

 body, hut it was not until 1883 that Ahlborn- first described the 

 microscopic appc.-iranccs of th<' epiphyseal oompl(x in which 

 he was able to observe two superposed vesicles. Ahlborn, 

 however, did not interpret these two vesicles as independent 

 evaiiinations from the roof of tin' interbrain, but considered 

 them as subdivisions of the epiphy>is. 



