3°6 



A CTINOP TER YGII 



lower forms, but may be stalked in the Teleostei. The ganglionic 

 cells become clearly stratified (Goronowitsch [ISO], Mayser [298], 

 Kabl-Riickert [340], Johnston, Mihalkowikz). 



Fig. 282. 



Median Longitudinal section of the brain of Aeipenser rutiiewus. (After Goronowitsch, from 

 Sedgwick's Zoology). Ch, cerebellum; ch, optic chiasma; ep, pineal body; hy, pituitary body : 

 pi, roof of telencephaion with choroid plexus; Af, roof of mesencephalon; pi, roof of jnyelen- 

 cephaloD ; s.v, saccus vasculosus ; r. cavity of telencephalon ; z, cavity of thalamencephalon. 



Pig. 283. 



Left-side view of brain of A, Aeipenser rutliemis ; and B, Amia ealva. (After Goronowitsch, 

 from Gegenbaur, Vergl. A not.) <»..■, auditory nerve : Ep, epiphysis : /•', facial nerve ; Gp, glosso- 

 pharyngeal nerve ; h and hy, hypophysis ; Hh, cerebellum ; /../, lobns inferior; L.ol, olfactory 

 lobe ; M, mesencephalon; N, myelencephalon ; o, optic nerve; pi, choroid plexus; 7V and 

 Tr", trigeminal nerve; s.v, saccus vasculosus ; Vg, vagus nerve. 



The urinogenital organs are discussed elsewhere (p. 365) ; but 

 it may here be mentioned that the cloaca is lost, the anus opening 

 separately in front, and the genital and urinary ducts lead into a 



