332 



Robert J. Terry. 



Opsanus Embryos 8 mm. in Length 



Epiphysis. The dorso-caudal direction of the -epiphysis at 

 this stage brings its posterior surface into contact with the mid- 

 brain (fig. 7, E). The organ is relatively shorter now and in form 



SEA 



S E A 



8 



Fig. 7. Median section of the pineal region of an Opsanus embryo of 8 mm. 

 H.E C, series no. 116, section no. 78. X 116.8. 



Fig. 8. Transverse section of an Opsanus embryo of 8 mm. H.E.C., series no. 

 115, section no. 36. X 116.8. 



Fig. 9. Transverse section of the pineal region of a Salvelinus embryo of 10 

 mm. H.E.C., series no. 455, section no. 42. X 84. 



somewhat oval. Its structure is essentially as in the 11 mm. em- 

 bryo and calls for no particular description. Just to the left of the 

 base of the epiphysis there can be seen in transverse sections 

 of the diencephalic roof an oval, compacted mass of nuclei pro- 



