558 FISHES. 



ties within the temperate and 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 ;" B. aurantiaca, the " Lemon-sole," which is 

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

 England, deeper water than the common Sole ; 8. variegata, 

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

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

 and Liachirus from the Indian coasts. 



Synaptura. — 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 Acsopia. 



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. 



Cyxoglossus. — 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 



