PISCES, TRUE FISH 457 



solution. "When glass beads are coated with wax and covered with 

 this solution they become artificial pearls. 



TYPICAL BONY FISH— YELLOW BULLHEAD AND SOME 

 COMPARISONS WITH YELLOW PERCH* 



The yellow bullhead catfish, Ameiuriis natalis, is widely distrib- 

 uted through the fresh waters of the United States. Its distribution 

 did not originally reach the Pacific coast, but during recent years 

 it has been successfully introduced. The natural range extends 

 throughout the Middle West, South, and well into the Southwest. 

 These fish will be the principal subject of this description, but there 

 will be some comparisons made with yellow perch, Perca flavescens. 



The bullhead inhabits nearly all sluggish streams, ponds, and 

 lakes. It lives along the muddy banks and around submerged rocks 

 and logs in the water. It is a very hardy fish and is able to thrive 

 in almost any aquatic condition. Perch lives in clear lakes and ponds. 



External Features 



The body is stout, the head is short and broad, and the mouth is 

 wide. There is a relatively small dorsal fin located anteriorly, an 

 adipose fin back near the tail, and a rounded caudal fin forming the 

 tail. Just anterior, to the caudal fin on the ventral side of the body 

 is a single, broad, bladelike anal fin. Anterior to this is a pair of 

 ventral or pelvic fins. Just posterior to the gills and in a lateral 

 position are the pectoral fins. The skin of Ameiurus is smooth and 

 without scales whereas the skin of perch is covered with ctenoid 

 scales. There are two pairs of nostrils on the head, as well as eight 

 feelerlike harhels. These are distributed, two dorsally, one attached 

 to the maxillary process at each side of the mouth, and four pale- 

 colored ones on the skin of the lower jaw. Perch has none. Ex- 

 tending along each side of the body is a lateral line. The eyes are 

 relatively small and without lids. On each side of the head is a 

 flaplike operculum, which covers the gills. The tail is homocercal. 

 The colors of the upper parts of the bullhead range from yellowish 

 green to dark brown. The sides are a lighter waxy yellow or yel- 

 lowish brown, and the ventral side is yellow. The dorsal barbels 

 are brown, while those ventral to the mouth are pinkish cream. 

 There is a darker longitudinal band running lengthwise of the anal 



•In collaboration with Rose Newman. 



