LUCIOPERCA SANDRA. 39 



head is elongated with a straig-ht upper outline^ and the cleft of the jaws 

 extending as far back as the middle of the eye. The species of this genus 

 are mostly found in rivers and lakes of the northern parts of the Old World 

 and America. Lucioperca marina, which is found in the Black and Caspian 

 Seas, is the only marine species. The North American species are distinct 

 from those of Europe. Two species occur in the fresh waters of the Euro- 

 pean Continent. 



Lucioperca sandra (Cuvieu). — The Pike-Perch. 



1 2 2 



Eins: 1 D. 1:]— 14-, £ D. , ^ ^_^.^ A. li_J^2 ^- ^^' ^- ^1^' ^- ^'^ ' 



The form of the body of the Pike-Perch (Fig. 14) , compared with that of 

 the Perch, is much more elongated and less compressed. The body is highest 

 in front of the dorsal fin, but that height is scarcely more than one-sixth 

 to one-fifth of the length of the fish. The head, measuring to the point 

 of the operculum, is about one-quarter of the length of the fish. The eye 

 is placed in the anterior third of the head, is sepai*ated from the eye of the 

 opposite side by its own diameter, and is distant from the extremity of the 

 snout one and a half times the orbital diameter. The external nostrils are 

 small, and near to the eye; the upper and lower jaws are equal. The maxillary 

 bone often extends behind the eye when the mouth is closed. The tongue is 

 smooth. Between the fine villiform teeth arranged in bands, which are seen 

 in both the upper and lower jaws, are tusk-like teeth, in the position of canines 

 at the corners of the mouth. The entire edge of the lower jaw carries an even 

 row of rather shorter pointed teeth, which extend behind the villiform teeth. 

 The villiform teeth are absent on the pre-maxillary bones, where only a few 

 large pointed incisors extend between the canines. The anterior teeth on 

 the palatine bone are stronger, and include longer teeth than those on its 

 hinder part. The vomerine teeth are small, and occur only in bands. As 

 the stronger teeth are often lost, owing to the predatory habits of the 

 animal, the dentition varies in different individuals. The vertical part of 

 the pre-operculum is finely serrated at its edge; the serrations on the horizontal 

 part are larger and uneven. The edge of the long bone, termed the supra- 

 scapula, also carries firm denticulations. The first gill-arch carries long 

 notched spines, termed gill-rakers, while the later arches have only pro- 

 minences, upon which denticulations are collected. There are seven braii- 

 chiostegal rays, which become successively smaller. 



The first dorsal fin is about as long as the head. It is conspicuously 

 spiny ; the spines arc pointed and jiowerful, and increase in length to the 



