382 



COLLEGE ZOOLOGY 



Tongue 

 Mouth cavity 



Ventral aorta 

 Pharynx 



Heart 



Sinus venosus 



Pericardial cavity 

 Liver 



Gall bladder 

 Pancreas 



Pelvic fin 



Olfactory nerve 



Cerebrum 



Optic lobe 



Cerebellum 



Medulla 

 — Skull 

 Gill 



Nerve (spinal) cord 



Esophagus 



Air bladder 



Spinous dorsal fin 



Dorsal aorta 



Air bladder 



Stomach 



Kidney 



— Rib 



Urogenital opening 



nterspinous 

 bone 



Neural spine 



Urinary bladder 

 Urinary duct 



Muscle 

 Soft dorsal fin 



Anal fin 



Caudal vein — 

 Caudal artery — 



'—Neural spine 

 Nerve (spinal) cord 

 Centrum 



Figure 255. General structure of a yellow perch. 



floor of the mouth cavity; it is not capable 

 of independent movement, but functions as 

 a tactile organ. The mouth cavity is fol- 

 lowed by the pharynx, on either side of 

 which are 4 gill slits. Food passes directly 

 to the stomach through a short esophagus. 



The stomach, intestine, liver, gall bladder, 

 pyloric ceca, and anus are shown in Fig. 

 255. The pancreas is located in the first loop 

 of the intestine; however, it is so diffuse 

 that it is not usually seen in gross dis- 

 section. 



