558 FISHES. 



ties witliiii the temperate anc^ tropical zones, with the excep- 

 tion of the southern parts of the southern temperate zone, in 

 which they are absent. Some enter or live in fresh water. 

 Nearly forty species are known. British are S. vulgaris, the 

 common "Sole;" S. aurantiaca, the "Lemon-sole," which is 

 rather a southern species, and inhabits, on the south coast of 

 England, deeper water than the common Sole ; S. variegata, 

 the " Banded Sole," with very small pectoral fins ; and >S'. 

 minuta, the " Dwarf-Sole." — Allied to Solea are Pardachirus 

 and LiacMj-us from the Indian coasts. 



Synapttjea. — Eyes on the right side, the upper in advance of 

 the lower. Cleft of the mouth narrow, twisted round to the left 

 side ; minute teeth on the left side only. Vertical fins confluent. 

 Scales small, ctenoid ; lateral line straight. 



Twenty species; with the exception of two from the 

 Mediterranean and coast of Portugal, all belong to the fauna 

 of the Indian Ocean. — Closely allied is Aesopia. 



Gymnachirus. — Mouth very small, toothless. Scales none, 

 lateral line straight. Eyes on the right side. The dorsal fin 

 commences on the snout ; caudal free. Pectorals rudimentary or 

 entirely absent. 



Two species from the Tropical Atlantic. 



Cynoglossus. — Eyes on the left side; pectorals none; ver- 

 tical fins confluent. Scales ctenoid ; lateral line on the left 

 side double or triple ; upper part of the snout produced back- 

 wards into a hook ; mouth unsymmetrical, rather narrow. 

 Teeth minute, on the right side only. 



Abundant in the Indian seas, and especially on the flat 

 sandy shores of China. About thirty-five species are known, 

 which rarely exceed a length of eighteen inches. They are 

 easily recognised by their long narrow shape (which has 

 been compared to a dog's tongue) and the peculiar form of 

 their snout. 



To complete the list of Pleuronectoid genera, the following 



