334 THE FLOUNDER FAMILY. 



up to 6'25 mm. They are deeply pigmented, with a short, 

 obtuse snout, and an acute angle at the lower jaw. The tail is 

 narrow and the belly prominent in the smallest example. The 

 tail becomes deeper and the abdomen less projecting at 7 mm. 

 One of the most interesting features is the presence of an 

 armature of spines, to which one of us had previously drawn 

 attention, best marked in specimens 10 to 1.5 mm. long, on 

 the head, behind the eye, on the articular region of the lower 

 jaw, and on the opercular region. These persist till they reach 

 25 mm., and Holt has even found traces of them in an 

 example 17.5 mm. in length. An air-bladder is present. At 

 13'5 mm. the right eye shows above the ridge. Mr Cun- 

 ningham, again, remarks that young brill swimming horizon- 

 tally at the surface occur in the south in May and June, 

 whereas turbot in this condition are later, viz. August and 

 September. 



Di- Petersen' also points out, after a spineless early stage, 

 the presence of spines on the head of the pelagic turbot of 7 

 (Plate XIII, fig. 3) to 15 mm. long, particularly over the 

 left eye, though also present on the right, on the operculum, 

 beneath the lower jaw, and at the upper end of the clavicle. 

 These, though disappearing, were still noticeable in one of 21 

 mm. Again in those of 7 — 8 mm. (Plate XIII, fig. 4) traces 

 of true rays occur in all the median fins, and the notochord is 

 boldly bent upward. In comparing it with a brill of the same 

 size it is evident that the turbot is in advance of the brill in 

 development. 



When the young turbot (Plate XIII, figs. 5 and 6) reach 

 the bottom, Petersen states that all the spines disappear, except 

 the intei'ocular cusp. The fins have the full number of rays, and 

 the form is like that of the adult. At 33 mm. the scales and 

 surface-spines (transformed scales) appear, but some specimens 

 are larger before these are developed. Young specimens of the 

 turbot and brill are distinguished, amongst other characters, 

 by the number of rays in the dorsal and the anal fins. In the 

 turbot, the rays of the dorsal range between 68 and 56 ; those 



' Danish Biol. Stilt. 1893, p. 131, Plates 1 and 2. 



