442 SOFT-FINNED GROUP. 



are exclusively carnivorous. In a fossil state the flat-fish are but poorly repre- 

 sented, and it is probable that they were not evolved till the commencement of 

 the Tertiary period ; the earliest known form being a turbot from the middle 

 Eocene of Monte Bolca, while a fossil sole has been described from the Miocene of 

 Wurtemberg. As a food-supply the flat-fish are of especial value, not only on 

 account of the large size, and abundance of their numerous representatives, but 

 likewise from the excellent quality and flavour of the flesh of the majority of 

 these. It is on the coasts of the temperate regions of the Northern Hemisphere 

 that the pursuit of these fish is carried out with the greatest energy and success. 



The least specialised member of the family (Psettodes erwmei), 



which ranges from the Red Sea through the Indian Ocean to China, 

 and also occurs on the West Coast of Africa, belongs to a group in which the teeth 

 and jaws are nearly equally developed on both sides, and is specially distinguished 

 by the dorsal fin commencing on the nape of the neck, whereas in all the other forms 

 it starts from above or in front of the eyes. In the Indian fish, which attains a 

 length of about 16 inches, the eyes are as frequently on the right as on the left 

 side, and the transposed one is situated nearly in the line of the dorsal fin. This 

 species is a connecting link between the other members of the family and ordinary 

 fishes, and is reported to swim at times in a vertical position. 



Having the jaws nearly equally developed on both sides, and the 



dorsal fin commencing above the eyes, the holibut {Hippoglossus 

 vulgaris) is one of two species forming a genus characterised by the eyes being on 

 the right side, and the teeth of the upper jaw arranged in a double series, those in 

 the front of the upper and on the sides of the lower jaw being enlarged. The 

 mouth is relatively wide. In colour the holibut is dusky brown, frequently 

 inclining to olive, on the dark side ; the opposite side being white and smooth. It 

 is the largest member of the family, ranging usually from 3 to 6 feet in length ; 

 one specimen with the latter length having a breadth of 30 inches, and a weight of 

 161 lbs. It is stated, however, that an example taken in the early part of this 

 -century off the Isle of Man was nearly double that weight. Holibut are found 

 near all the northern coasts of Europe, as well as those of Kamschatka and Cali- 

 fornia, generally frequenting banks at some distance from the shore, in water of 

 from fifty to one hundred fathoms in depth, where they often associate in consider- 

 able numbers. The flesh is coarse, and of inferior flavour. This fish is shown in 

 the upper figure of the coloured Plate. 



In the genus typically represented by the turbot {Rhombus 



maximus) the dorsal fin commences on the muzzle in advance of the 

 •eyes ; the eyes are on the left side ; the mouth is wide ; and the jaws are furnished 

 with a single series of equal-sized villiform teeth, while there are also teeth on the 

 vomer. Scales are either very small or wanting. The genus includes seven species, 

 ranging over the North Atlantic and Mediterranean, but those on the two sides of 

 the Atlantic are different. The turbot, which attains a yard in length, and is by 

 far the best food-fish of its tribe, is exclusively European, and has the pelvic fins 

 •distinct from the anal, and no scales ; the general colour being greyish or brownish, 

 sometimes spotted with a darker tint. On the other hand the brill (Rh. Icevis), 

 which is likewise European, is a smaller fish, of more oval shape, with the body 



