FLAT-FISHES. 



557 



Pleuronectes. — Cleft of the mouth narrcw, with the denti- 

 tion much more developed on the blind side than on the coloured. 

 Teeth in a single or in a double series, of moderate size ; palatine 

 and vomerine teeth none. The dorsal fin commences above the 

 eye. Scales very small or entirely absent. Eyes generally on 

 the right side. 



This genus is characteristic of the littoral fauna of the 

 northern temperate zone, a few species ranging to the Arctic 

 circle. Twenty-three species are known, of which the fol- 

 lowing are the most noteworthy : P. platessa, the " Plaice," 

 ranging from the coast of France to Iceland; F. glacialis, 

 from the Arctic coasts of North America ; P. americanus, the 

 transatlantic representative of the Plaice; P. limanda, the 

 common " Dab ;" P. microcephalics, the " Smear-dab ;" P. 

 cynoglossus, the " Craig-fluke;" P.flesus, the "Flounder." 



Ehombosolea. — Eyes on the right side, the lower in advance 

 of the upper. Mouth narrower on the right side than on the 

 left ; teeth on the blind side only, villiform ; palatine and 

 vomerine teeth none. The dorsal fin commences on the fore- 

 most part of the snout. Only one ventral which' is continuous 

 with the anal. Scales very small, cycloid ; lateral line straight. 



This genus represents Plewronectes in the Southern Hemi- 

 sphere, but consists of three species only, which occur on the 

 coasts of N'ew Zealand, and are valued as food-fishes. 



Other genera, with narrow unsymmetrical mouth, in which 

 the upper eye is not in advance of the lower, and which have 

 pectoral fins, are Parophrys, Psammodiscus, Ammotretis, Pel- 

 torhamphus, Nematops, Zceops, and Poecilopsetta. 



Solea. — Eyes on the right side, the upper being more or less 

 in advance of the lower. Cleft of the mouth narrow, twisted 

 round to the left side. Villiform teeth on the blind side only ; 

 vomerine or palatine teeth none. The dorsal fin commences on 

 the snout, and is not confluent with the caudal. Scales very 

 small, ctenoid ; lateral line straight. 



" Soles " are numerously represented in all suitable locali- 



