CHAP, xix.] FLAT-FISHES. 471 



mortem change. Eight pelvic fin dark, but the left was whitish, speckled with 

 black. Nostrils normal. The eye of the right (blind) side was placed almost 

 entirely on the left side, but not completely so, for it could be seen to some extent 

 in profile from the right side. The notch separating the dorsal fin from the head 

 was rounded, and extended to about the level of the posterior margin of the left eye. 

 There were about 6 chief fin-rays borne by the prominence above the eye. The fish 

 seemed to be in all respects healthy and well grown. Paris Mus., numbered 

 ^90^:310. [This specimen was kindly shewn to me by Prof. Vaillant.] 



Similar specimen, also having white patch on operculum DUHAMEL DU MONCEAU, 

 I. c. See also Fig. 152, from YARRELL, Brit. Fishes, 3rd ed., i. p. 643. 



The specimen described by DONOVAN (Brit. Fish., 1806, iv. PI. xc.) under the 

 name "Pleuronectes cy clops" was in Steenstrup's opinion a young Brill having this 

 variation. In this specimen the right eye is seated on the top of the head and is 

 seen in profile from the right side. The right side was coloured like the left, but 

 was not so dark. The dorsal fin began behind the right eye. This specimen was 

 found in a rock-pool "iuveloped in a froth" said to have resembled cuckoo-spit. 



731. Zeugopterus punctatus (Miiller's Topknot). This fish is very liable to mal- 

 formations of the anterior end of the dorsal fin, causing it to form an arch over the 

 eyes. YARRELL (quoting COUCH), Brit. Fish., 3rd ed., i. p. 648. 



732. "Platessa oblonga" De Kay (American Turbot) ; specimen having both sides 

 darkly coloured ; upper eye placed on the top of the head ; dorsal fin separated by a 

 notch. STORER, Mem. Arner. Ac. Set., vin. p. 396, PI. xxxi. fig. 2 b. 



733. Pleuronectes platessa (Plaice) : specimen completely and similarly pigmented 

 on both sides far from rare. In a specimen thus coloured the ' tubercula capitis ' 

 were as strongly marked on the one side as on the other. In several examples the 

 anterior end of the dorsal fin was separated from the head, GOTTSCHE, Arch. f. 

 Naturg., 1835, n. 1, p. 139. 



734. Pleuronectes flesus (Flounder) : several specimens found at Birkenhead, having 

 a deep notch of this kind above the eyes. These fishes were 'very dark brown 

 (almost black) on both sides.' In the length of the fins these examples differed 

 somewhat from the Flounder, HIGOINS, Zoologist, 1855, p. 4596, fig. Specimen of 

 this kind figured by TRAQUAIR, Trans. Linn. Soc., 1865, xxv. p. 288, PI. xxxi. figs. 8 

 and 9. See also NILSSON, Skandin. Fauna: Fiskarna, Lund, 1855, p. 621 ; COUCH, 

 Brit. Fishes, 1864, in. p. 198. 



/35. Solea vulgaris. Many authors mention Soles coloured on both sides, but I 

 know no good description of one. YARRELL (1. c., p. 669) says "we have not seen 

 the Solea Trevelyani of Ireland (Sander's News-letter, 16th April, 1850). It is 

 dark-bellied and is described as bearing a projection on the head like the monstrosity 

 figured on p. 643." DUHAMEL DU MONCEAU (I. c., PL i. figs. 3 and 4) represents a 

 sole darkly coloured on both sides. The dorsal fin is shewn in its normal state, 

 not separated from the head. No special description is given, and as the author 

 does not state that he had himself seen such a sole the figure was perhaps not 

 drawn from an actual specimen. A sole with the under side piebald is described in 

 Zool. x. p. 3660. 



In connexion with this evidence STEENSTRUP refers to a small flat- 

 fish, Hippoglossus pinguis, found in a few localities in Scandinavian 

 waters, having a form almost intermediate between a "flat" and a 

 "round" fish. The eye of the "blind" side is exactly on the top of 

 the head and can be seen in profile from the blind side. The blind side 

 is nearly as muscular as the upper side, and its skin is yellowish-brown 

 in colour and is only slightly paler than that of the upper side. The 

 dorsal fin begins behind the eye, not arching over it. Steenstrup 

 looked on this creature as representing in a normal form the "double" 

 condition presented as a variation in the cases we have been speaking 

 of. See description and figures in SMIT'S edition of FRIES, EKSTROM 

 and SUKDEVALL'S Hist, of Scand. Fishes, 1893, pp. 416 and 417. 

 SMIT makes a new genus, Platysomatichtliys, for this animal. 



