and of the stone cat. In the 

 former it is free, while in the 

 latter it is said to be adnaie 

 to the back. 

 (b). Write the fin formulas of the perch, 

 (c). Make a table which will contrast the 

 fins (including type of tail) of the 

 perch, bullhead, stone cat, and gar. 

 (i). Types of scales. 



( I ) . Placoid — Froni a ray. Draw, 

 (2). Ganoid scales — Bony plates from the sturgeon; 

 rhombic plates from a gar. Drawing of each. 

 (3 ) . Cycloid — From white sucker. Study an ordin- 

 ary scale and one taken from the lateral line. 

 Drawing of each. Examine the scales of an 

 eel. Make a drawing of the scale arrange- 

 ment and an enlarged drawing of a single 

 scale. Repeat for the burbot. What name 

 is applied to each? 

 (4). Ctenoid — From the perch. Draw. 



(j); MaxiUaries — Flat, triangular bones forming the lateral 

 margins of the upper jaw. Identify. Determine 

 extent. Compare with the maxillaries of the white- 

 fish, in which note the supplemental maxillary in the 

 dorso-caudal angle. Draw. Examine the maxillary 

 of the bullhead. Result? 

 Examine the maxillary of the porgy and note that it 

 slips under the edge of the preorbital bone, 

 (k). Premaxillaries — Forming the cephalic margins of the 

 ; upper jaws. Are they protractile, i. e., are they capa- 

 ble of being pulled cephalad leaving a groove over the 

 top of the snout? Compare with the bulUiead. 

 Result?. 



(1). Snout — Distance from the tip of upper jaw to the front 

 margin of eye. 



(m). Caudal Peduncle — The region in front of the caudal fin. 

 Compare the perch and the mackerel. What 

 characters are found associated in the mackerel? 



(n). Make a drawing of the left side of the perch. Repre- 

 sent the mouth open and the fins extended. When 

 6 



