THE PINEAL BODY 



117 



1889 first discovered the pineal organ in embryos. Eycles- 

 hymer 112 in 1892 made a more extensive study of this organ and 

 found the epiphysis to be a long, glove-finger shaped struct- 

 ure. The cells in the under wall were somewhat larger than 

 those in the upper wall and some of them contained pigment. 



2. Amphiuma means. Osborn ('83). 287 In this species there 

 is a marked plexiform paraphysis, while the pineal organ extends 

 forward as a small sac over the commissura habenularis. 



3. Menopoma alleghaniense. Osborn ('84). 288 The pineal 

 organ in this species is a saccular evagination with a lumen 

 opening into the third ventricle. 



4. Menobranchus. Osborn ('84). 288 In this form the pineal 

 organ is a long, flattened sac completely detached from the 

 brain. Kingsbury 204 in 1895 showed that there is a well-marked 

 paraphysis and also that there are nerve fibers in connection 

 with the pineal organ. 



5. Salamandra maculosa. Burckhardt ('91). 43 The pineal 

 organ in this species is a short, hollow, and rudimentary stalk. 

 There is a flattened end-vesicle in which there appears evidences 

 of degeneration. 



6. Diemyctylus viridescens. Gage ('93). 1SS The pineal organ 

 in this form is very small in the adult and there is no lumen in 

 any portion of it, There is, however, a well-developed para- 

 physis. 



7. Desmognathus fuca. Fish ('95). 119 The pineal organ in 

 this species is a small compressed structure. It contains no 

 lumen in the adult, but in the larva the organ is hollow. 



8. Triton taeniatus, cristatus and alpeslris. deGraaf ('86) 1 " 

 The pineal organ in these species is rudimentary. There is a 

 short, hollow stalk and a flattened end-sac in which there is 

 evidence of a process of degeneration. This same form was 

 studied by Blanc 34 in 1900 with practically the same results. 



9. Spekrpes fuscus. Galeotti ('96). 14 In this species the 

 pineal organ is oval and hollow. The end-sac is directly in 

 connection with the commissura habenularis and there is no 

 stalk. The cells have an epithelial arrangement and are formed 

 in alveoli, giving the structure a glandular appearance. 



