Pisces. 7 1 



The remaining fins are called paired fins ; the pair back of the 

 head are the pectoral fins, and are considered as representing 

 the fore limbs of the higher animals ; the lower pair (usually farther 

 back) are the pelvic fins, representing the hind limbs of higher 

 animals. Take the pelvic fins between the thumb and finger to 

 feel their bony support ; rest the fish on its back, and press the 

 thumb and forefinger of the other hand on the bony structures 

 at the bases of the pectoral fins; move the pelvic fins about to 

 determine, as far as possible by feeling, the relations between 

 the bones supporting the two pairs of fins. 



3. Open the mouth of the fish by pulling its lower jaw down as 

 far as possible ; the bone which forms the border of each side of 

 the upper lip is the premaxillary ; note its extension backward on 

 the middle of the snout ; observe the fine teeth on it. Observe 

 their size, shape, arrangement,- and the direction in which they 

 point. The paddlelike bone, back of the premaxillary, outside of 

 the mouth, is the maxillary. The bone on each side of the lower 

 jaw is the dentary. 



Which of the above-named bones bear teeth? Open and shut 

 the mouth repeatedly, watching the movements of these parts, 

 and their relations to each other. 



Back of the premaxillary, in the front part of the roof of the 

 mouth, is a patch of teeth, borne on a bone called the vomer ; 

 extending backward from the vomer, on each side of the roof of 

 the mouth, are rows of teeth on the palatine bones. 



Examine the short tongue ; feel its surface with the tip of the 

 finger, or scrape it with the head of a pin ; examine also the whole 

 of the inside of the mouth, to see if there are more teeth than 

 those mentioned. 



4. Note the shape and position of the eyes; with the handle of 

 the forceps press on the eye at various points near its margin, to 

 see its range of motion ; watch the roof of the mouth while press- 

 ing the eye, also press outward on that part of the roof of the 

 mouth nearest to the eye. Compare the eyes with human eyes. 

 Are eyelids present? Observe a thin bone embedded in the skin 



