438 



ZOOLOGY. 



superior (Os) and inferior (Oi), arise from the front of the 

 orbit near the interorbital septum. The disposition of the 



Fig. 397. Anatomy of the brain of the Gunner, dorsal and side view. B. 01, olfac- 

 tory lobea ; the crura and the thalami not represented. Drawn by C. S. Minot. 



recti is very constant, but the obliqui vary considerably in 

 their origin in different Vertebrates. 



If a perch be cut through transversely, so that the section 

 passes through the fore-part of the 

 air-bladder, and the anterior portion 

 then looked at from behind, a very 

 instructive view will be obtained, as 

 in Fig. 398. The best sections can be 

 made by first freezing the fish. The 

 vertebral column ( F) appear? a little 

 above the middle ; overlying it is the 

 neural canal with the spinal cord ; im- 

 mediately below it is the descending or 

 dorsal aorta (Ao), on either side of 

 which follow the kidneys (A"), resting 

 directly upon the air-bladder (Bl). 

 Lowermost is the body-cavity, with 

 the stomach (S'), and intestine (In), 



In 



surrounded by the liver, which has & n a ot Cunner -- Drawn by Cl s 

 been almost entirely removed. The 



rest of the section is occupied by muscles, which, it will thus 

 be seen, make up the main bulk of the body. (Minot.) 



