242 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY, 



P4REEH. — Optic Chiasma. 



EXPLANATION OF THE PLATE. 



All figures represent dorsal views of brains of teleosts from wliich the cerebral 

 hemispheres have been removed, thus exposing the optic nerves, chiasmata, and 

 parts of the tracts. The optic lobes, cerebellum, and medulla are sliown in each 

 instance, as well as the outline of the eyeballs. 



Fig. 1. Gadus morrhua Linn. Left optic nerve dorsal. 



Fig. 2. Gadus morrhua Linn. Right optic nerve dorsal. 



Fig. 3. Lopliopsetta niaculata (Mitchill). Sinistral species. Right optic nerve 



dorsal. 

 Fig. 4. Pseudopleuronectes americanus ( Walbaum). Dextral species. Left optic 



nerve dorsal For the best exposure of the chiasma the brain is viewed 



from an antero dorsal position , hence the optic lobes are somewhat 



foreshortened. 

 Fig. 5. Paralichthys californicus (Ayres) Sinistral species. Sinistral individual. 



Right optic nerve dorsal. 

 Fig. 6. Paralichthys californicus (Ayres). Sinistral species. Dextral individual. 



Right optic nerve dorsal. 

 Fig. 7. Platichthys stellatus (Pallas). Dextral species. Sinistral individual. 



Left optic nerve dorsal. 

 Fig. 8. Platichthys stellatus (Pallas). Dextral species. Dextral individual. 



Left optic nerve dorsal. 



