480 



MANUAL (")]■• ZOOLOGY 



(Fig. 289, c. b) is of great size, and has a large median portion 

 and two small lateral lobes or flocculi (/) ; the surface of 

 the middle lobe is marked by grooves passing inwards in a 

 radiating manner and carrying with them the grey matter, 

 the extent of which is thus greatly increased. The hemi- 

 spheres (c. h) extend backwards to meet the cerebellum, 

 and the optic lobes (0. I ) are thereby pressed outwards so 

 as to take up a lateral instead of the usual dorsal position. 





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ni/ 



pet 



Fig. 290 —The eye. A, in sagittal section: B, the entire organ, external aspect; 

 en, cornea; ch, choroid; cl. pr, ciliary processes; z>, iris; /, lens; opt nv, 

 optic nerve; pet, pecten; rt, retina; scl, sclerotic; scl. j>l, sclerotic plates. 

 (After Vest and Yung.) 



The eye (Fig. 290) is not even approximately globular, 

 but has the form of a biconvex lens. Sclerotic plates 

 are present, and there is a large pecten in the form of a 

 plaited and strongly pigmented membrane projecting into 



