530 ACANTHOPTERYGII. 



SECTION VIII. 



OSSEOUS FISHES 



FIRST ORDER. ACANTHOPTERYGII, (Gr. 'axa^fla, dkantha, a spine ; 



pteron, wing.) 



The CTENOIDS, or ACANTHOPTERYGIIANS, including three- 

 fourths of all known fishes, are almost all marine. They are 

 ornamented with hard, shining, tooth-like scales of beautiful 

 colors. The spiny fins of most of them are constructed for long 

 continued motion. 



FAMILIES. 



(I) Percida, (Gr. perke, a kind of fish.) 



THE PERCHES. These comprise one-seventh of all spine- 

 rayed Fishes. Most of them, including the Gropers or Mailed 

 Perches, are marine, but the typical species, the Common Perch, 

 of Europe, (Perca fluviatilis,) with two separated dorsal fins, 

 the rays of the first spinous, of the second flexible, is found only 

 in fresh water. To this nearly corresponds the YELLOW Perch, 

 P. jlavescens, the most conspicuous of the numerous North 

 American species, and found both in salt water and fresh. In 

 1825, Yellow Perch were transported from Skaneateles to Otisco 

 Lake and Onondaga Lake, and appeared to thrive after the trans- 

 fer. They are common in ponds and streams, and in all the 

 great lakes. The eggs of the Perch are of the size of a poppy 

 seed, and joined together by a viscid substance, in long strings. 

 Among the most remarkable fishes of this group are those in- 

 cluded in the genus Polynemus, (Gr. polus, many ; nema, a 

 thread or filament,) distinguished by having the ventral fins in- 

 serted farther back than the pectorals, and also for having nu. 

 merous long flexible filaments placed near the latter fins, from 

 four to ten on each side, and sometimes twice the length of the 

 body. Interest attaches to these fishes from the fact that the 

 bladders of several species yield pure isinglass. The SULEAH 

 Fish of India, P. sele, is the one from which it is said to have been 

 first procured. Shoals of this species are found in the estu- 

 aries of the river Ganges ; they are three to four feet in length, 

 and eight to ten inches in depth. The species P. Americanus 

 has several rays attached to the pectoral fin. It is about a foot 

 in length, and of a silvery color. All the fishes of this family 



