8 



CONARIO-HYPOPHYSIAL TRACT. 



prolongation of the third ventricle exists in all Osseous Fishes. 

 The ' infunclibulam ' is commonly short and thick, so that 

 the hypophysis is almost sessile, as in the Cod ; but in the 

 Lophius the infundibulum is longer than the entire brain, and 

 the hypophysis lies at the fore part of the cranial cavity far 

 in advance of the cerebral lobes (but in vertical parallel with 

 the palate). In the Cod the hypophysis, fig. 185, j?, is a sub- 

 spherical mass, with an irregular surface almost half the size 

 of the human ' pituitary gland,' and illustrating the vast 

 proportional size of this constant appendage to the brain of 

 Fishes"-*. 



Fig. 2. 



Protopterus. — 1. Neural axis. 2. Notochord. 3. Cerebellum. 

 4. Optic lobe. 5. Poremost branchial arch. 6. Cerebrum. 7. Pineal 

 bod3^ 8. Pituitary body (together, the conario-hypophysial tract). 

 9, Oral cavity. 10. Branchial cavity. 11. Stomach. 12. Intestine. 

 14. Yent. 15. Heart and chief blood-vessels. 



In the Skate [Baia batis) the extension of the pineal part of 

 the tract in question reaches beyond the cartilaginous roof of 

 the brain-case ; in the spiny Dogfish {AcantJdas) its progress 

 is there arrested; but the cavity in which it is lodged testifies 

 to its destination, and here it retains, as a dilated part, more 

 of its primal character. In all the Elasmobranchs the pineal 

 part of the arrested gullet is an elongate tube, dilated at its 



* Anat. Yert. i. p. 280. 



