23 



CHAPTER II. 



FRESH- WATER FISHES OF THE ORDER ACANTHOPTERYGII. 



FAMILY PERCID.E— Genus Perca : The Eiver Perch— The Bass- Genus Percarina : 

 Percarina Demidoffii— Genus Acerina : The liufE or Pope — Aoerina schri.etzer — Acerina 

 rossica— Genus Lucioperca: The Pike-Perch — The Pike- Perch of the Volga — Genus 

 AspRo: The Zingel— The Apron— The StreT)er— FAMILY COTTIDiE— Genus Cottus : 

 The Miller's Thumb— Cottus pcjecilopus— Father Lasher— FAMILY GOBIID^— Genus 

 GoBius: Species of Goby— The Polcwig— FAMILY BLEXNIID^E— Genus Blennius— 

 FAMILY ATHERINIDi^— Genus Atherina : The Sand Smelt -FAMILY MUGILID.E 

 —Genus Mugil : The Grey Mullet— FAMILY GASTEROSTEID.E— Genus Gasteros- 

 teus : The Sticklebacks. 



Family: PERCID^. 



GrENUS : PerCR (ArTEDI). 



The Perch is the type of the group Percina^ a tribe oE about eighteen 

 genera of fishes, which agree in having an oblong and elevated form of body, 

 denticulated opercular bones, and ctenoid scales, with two dorsal fins, dis- 

 tinguished by a number of spines, which is constant in each species. The 

 Perch is found in rivers and lakes. The variety Perca flavescens ranges over 

 the United States and Canada, and the Canadian variety, Pe7-ca gracilis, is 

 probably only a variation of that type. The number of spines in the first 

 dorsal fin is greater in Perca than in the marine Bass {Lahrax), which is its 

 nearest ally, a genus which lives alike in mouths of rivers and in the 

 seas of the northern parts of the world. The Perch family have the teeth 

 simple and conical, have no barbels to the mouth, and the lateral line of 

 mucus pores extends from the head to the caudal fin. 



Perca fiuviatilis (Linn.eus). — The River Perch. 



1 D. 13—10, 2 D. 1—2/13—15, A. 2/8—9, V. 1/5—6, P. 11—17, C. 17, 



7 9 



Scales: lateral line 54 — 72, transverse ^ --- 



1^—18. 



The Perch (Fig. 10) is sub-ovate in body, three to four times as long as 

 high, and moderately compressed from side to side. Its greatest height occurs 

 above the ventral fins. The length of the head, to the extremity of tbe 

 operculum, is nearly equal to the height of the body, but may be a little 

 longer or a little shorter. The eye varies in relative size with age, and 

 is placed from one to one and a third times its own diameter behind and 



