34 ANACANTHINI. 



Varieties in colour. 



Pleuronectes passer, Linn. Syst. Nat. i, p. 459 ; Bloch, 1. c. p. 57, t. 1. 



Pleuronectes roseus, Shaw, Nat. Misc. vii, p. 238, and Gen. Zool. iv, p. 302, 

 pi. 43.* 



Platessa camaria, Brown, Edin. Journ. of Nat. and Geol. ii, p. 99, t. ii. 



Platessa flesus, var. marmorata, Nord. in Demid. Voy. Russ. Pise. pi. xxviii, 

 f. 1. 



Flesus vulgaris, Moreau, Poiss. France, iii, p. 299. 



Varieties in form. 



Platessa flesus, Thompson, Proc. Zool. Soc. 1837, p. 60, and Ann. Mag. Nat. 

 Hist. 1865 (3), xv, p. 361, pi. xviii. 



Flounder, Couch, Fish. Brit. Isles, iii, p. 195, pi. clxxv. 



B. v, D. 60-62, P. 10, V. 6, A. 39-45, C. 14, L. 1. 85, Ccec. pyl. 2, Vert. 

 12/23-24. 



Length of head 4, of candal fin 5f , height of body 2^ in the total length. 

 Eyes less than 1 diameter apart, and the lower slightly in advance of the upper. 

 The eyes are so prominent that they are capable of observing objects on both sides 

 of the head. Lower jaw in advance of the upper. The length of the maxilla 

 equals about 1/4 that of the head, but does not reach to beneath the eyes. Anterior 

 nostril tubular, having a small opening : posterior one oval with wide lips. An 

 obtuse ridge passes from the interorbital space to the lateral-line. Teeth 

 conical, blunted, two rows in the upper and one in the lower jaw : the outer row 

 on the upper jaw of the blind side consists of 15 teeth ; the corresponding row in 

 the lower jaw of about 17. Fins dorsal commences opposite the middle of the 

 upper eye, its longest rays are in the posterior half of the body. Pectorals on the 

 two sides similar, and about 1/4 as long as the head. Ventrals free. A strong 

 spine, pointing forwards, exists before the base of the anal fin, which latter is 

 similar to the dorsal. Caudal cut square. Scales small, cycloid : rudimentary 

 ones on the cheeks. A rounded and rough tubercle between the bases of the 

 dorsal and anal rays. Lateral-line commencing opposite the angle of the mouth, 

 curves round the lower eye, and having joined the interorbital ridge, is continued 

 to the centre of the base of the caudal fin. Ccecal pylori short. Colours vary 

 very considerably, and depend upon that of the ground of the locality which they 

 inhabit, but even then scarcely two will be found to be exactly similar. The 

 colour of the upper side is generally olivaceous-brown, with or without darker 

 blotches. Occasionally examples are very dark, when they are termed sea- 

 flounders. The under surface is white. 



Young plaice and flounders of equal size may be distinguished, prior to the 

 appearance of tubercles along the bases of the dorsal and anal rays of the latter, by 

 the plaice having distinct scales, whereas they are rudimentary in the flounder. 



Pleuronectes flesus, P. luscus, and P. Italicus are considered one species by 

 Steindachner (Site. Ak. Wiss. Wien. 1868, lvii, p. 719). 



Varieties in colour. Double examples or such as are coloured on both sides 

 are not uncommon : also reversed ones. These last the fishermen persuaded 

 Donovan were a distinction of sex : Linna?us, Bloch, &c, considered such to be 

 distinct species. Some are partially or enth'ely albinos. Newman (Zool. xiii, 

 1855, p. 4596) records an albino-flounder with red eyes. " In 1862 an albino 

 variety was brought to me. Both sides were white, and the fins and eyes pink " 

 (Lowe, Norfolk Faun.). In some there are orange spots somewhat similar but 

 usually less vivid than seen in the plaice. On February 22nd, 1882, I obtained a 

 number from Brixham all having orange spots similar to the plaice, and was 

 informed that this is an appearance peculiar to spring-time. Thompson observes 

 that the examples he examined thus marked were taken in March. Some are of a 

 rosy hue, termed Pleuronectes roseus (Shaw) : or of a flesh-red, with irregularly but 

 distantly placed dark-coloured spots, Platessa camaria (Brown). Higgins (Zool. 

 xiii, 1855, p. 4596) remarks on one he terms Platessa melanog aster, notched above 



