THE TELENCEPHALON IN CYCLOSTOMES 401 
Eee aes primordium 
hippocampr 
bulb olf ih 
f 
SS 
SS Se 
NNN 
37 
Fig. 36 Cryptobranchus allegheniensis. Transverse section through the tel- 
encephalon behind the cerebral commissures. The remnant of the primordium 
hippocampi in the telencephalon medium appears on the left side to the right of 
the letters p.h. 
Fig. 37 Necturus. Sketch of the right half of the forebrain as seen from the 
medial surface. This figure is introduced merely to show the general relations of 
the medial zona limitans which extends rostrally from the interventricular foramen 
and separates the medial olfactory nucleus and primordium hippocampi. Its 
formation has been brought about by the evagination of the region which in the 
brain of cyclostomes lies rostral to the foramen. Compare figure 5. 
