852 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



bottom, but this is conjectural. At any rate, the border of the marginal fin, at this 

 and the subsequent stage elsewhere figured, is so translucent as to be generally in- 

 visible, only the pigment-touches arising from the border of the muscle-plates being seen. 

 The other parts of the head and body, as well as the ventral surface of the abdomen, are 

 speckled with ochreous and black pigments. It would seem that the pale buff or yellowish- 

 white pigment of the early larva is transitory, for by and by the ochre-yellow, beginning 

 at first as very minute points over the head and body, gradually spreads and supersedes 

 the yellowish-white, which disappears. The differentiation between the two is clearly 

 seen at certain stages, the yellow being characteristic of the body, the pale buff or whitish 

 of the marginal fin. The pectorals have their fan-like distal regions directed forward, so 

 that the larva seems to row itself onward by their rapid motion. The basal parts of the 

 pectorals are also invaded by the yellowish pigment. The eyes are silvery with black 

 pupils, and a dark arch occurs superiorly. The great depth of the head and the prominent 

 ridge over the optic lobes are characteristic. Moreover, the skin-fold along the median- 

 line of the abdomen next day was marked by a central hiatus, so that it formed two 

 portions. Further, the anterior one in a day or two became broad and almost vesicular. 



Zeugopterus jpunctatus. — A female example distended with ova was obtained in a pool 

 near the laboratory, on the 16th May. Most of the ova were unripe, but here and there a 

 translucent egg (PL I. fig. 6) occurred, especially anteriorly. They had a diameter of '042, 

 that of the conspicuous oil-globule being "008. Though, in all probability, not so large as 

 perfectly mature eggs discharged into the sea, the size is approximative. As might be 

 expected from the comparative scarcity of the adult off the eastern shores, the pelagic ova 

 are extremely rare in tow-nets ; indeed, so far as known, none have been met with. 



A post-larval example, 9 mm. long., was captured by the mid- water net at 25 fathoms, 

 south-east of the Island of May, 30th August 1886, though unfortunately it was consider- 

 ably injured. It is easily distinguished from the turbot of the same size by the much 

 larger bright silvery eyes, and by the outline of the body. The right eye is prominent 

 on the edge and its axis is directed laterally. The abdomen appeared to be prominent. 

 It is an older fish than the turbot of the same length. 



The size and prominence of the eyes in the latter stage is noteworthy, for when the 

 fish reaches the length of 3^ inches they are proportionally less, and moreover they are 

 deeply sunken. 



Unknown Larval Pleuronectid ? (A). — When using the tow-net on July 9, 1884, on a 

 trawling expedition 47 miles east by south of the Island of May, and over very rich ground, 

 a larval fish about 3 mm. was obtained by one of us. At first sight (after preservation) 

 it resembled a heteropod, for a cylindrical process projected from the anterior end, and the 

 position of the yolk-sac and other features increased the likeness. The anterior process, 

 however, is a hernia cerebri, and it must be remembered that the optic lobes in the Pleuro- 

 nectids are prominent. The mouth is indicated by a faint slit. The marginal fin is well 

 marked, extending from the front of the head to the tail, then forward to the anus. Here 

 it splits, a fold running along each side of the yolk-sac to the posterior part of the mandible. 



