CHAP. VIII.] AND OF AMPHIBIA. 117 



' hypoaria.' These bodies are well developed in the 

 Perch, and in the Cod (figs. 51, 57). Their use is un- 

 known, and it is remarkable that they are structures 

 peculiar to the brain of Fishes. 



In connection with the optic lobes there are also two 

 peculiar structures, one above and the other below, known 

 as the ' Pineal ' and ' Pituitary ' Bodies (figs. 53, s ; 60, 3, o ). 



In front of the optic lobes are the already men- 



FIG. 52. FIG. 53. 



FIG. 52. Brain of Carp. (Ferrier.) A, Cerebral lobes ; B, optic lobes ; c, cerebel- 

 lum and medulla. 



FIG. 53. Upper aspect of the Brain of a Ray, or Skate (Raia batis). 1, Olfactory 

 lobes; 2, the conjoined cerebral lobes ; 3, the pineal gland ; 4, optic lobes; 5, cere- 

 bellum ; 6, medulla, with ganglionic projections. (Mivart.) 



tioned Cerebral Lobes. They, like the cerebellum, have 

 no obvious connection with nerves, and vary much in 

 size in different Fishes, though they are mostly, as in the 

 Carp (fig. 52) and the Perch (fig. 50), smaller than the 

 optic lobes. 



The Cerebral Lobes are smallest in the Lamprey and 

 its allies, in the Herring, and in the Cod ; while they are 

 most developed in the Skate, the Shark, Polypterus, 

 and Lepidosiren. In the Skate (fig. 53), they coalesce 



