DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 841 
ordinary views the body appears to be almost linear. A peculiar feature is the presence 
of minute dark pigment-specks on the ventral lobe of the marginal fin, whereas into the 
dorsal lobe (ef) only one or two of the yellowish corpuscles pass from the line of the 
body. In this early stage the otoliths are remarkably small—much less, for instance, 
than in the fluke of the same age. The larva swims actively at the surface of the 
water, and is not easily noticed except by its large iridescent eyes, which now and 
then exhibit a golden sheen. Like some other young forms already described, it floats 
head downward in the water, besides frequently boring its snout into the sand at the 
bottom of the vessel. When at rest it lies upon its side at the bottom, and if the 
background be dark the yellowish pigment is conspicuous, especially in the caudal 
region. A perceptible increase in length took place within a few days after emer- 
gence. There is so little difficulty in hatching these ova, that this species could be 
multiplied in any suitable locality which it did not already inhabit. Mr CunnincHam * 
describes the yellowish spots as being in three rows on the lateral region of the embryonic 
plaice. 
In April large numbers of young pleuronectids at and near 12 mm. in length occur in 
St Andrews Bay. The eyes in these are generally asymmetrical, though in the smallest 
forms very slightly so. In the most advanced the left eye projects above the dorsal ridge, 
but is mainly used for vision on its own side. The blackish pigment-corpuscles are chiefly 
developed along the ventral margin of the body, though in some the sides posteriorly, 
and the posterior half of the dorsal margin, have a few specks. The terminal region of 
the notochord varies from a long dorsal filament to a mere trace beyond the hypural 
elements in the older examples. 
The foregoing may represent both the young of the plaice and the common flounder, 
the earlier post-larval stages in spirit not yet having been clearly separated. 
At the mouth of the Thames, young plaice 14 inch and upwards abound in the nets 
of the shrimpers in October, and similar forms are met with at a later period at the 
margin of the sandy beach at St Andrews. In June and July, at the latter place, the 
smaller forms range from 24 to 3} inches, and these are probably the young of the 
previous season. It is a noteworthy feature in connection with this and other species, 
that the larger forms are characteristic of the deeper water, while the smaller, from 11 
inches downward, abound in sandy bays (inshore water). The mature fishes (z.e., those 
with the reproductive organs fully developed), as formerly shown, are thus mostly beyond 
the three-mile limit. 
Pleuronectes flesus, L.—No form is better adapted for studying the development of 
pelagic Teleostean ova than this, though, as one of us has elsewhere pointed out, 
specimens in confinement seldom deposit healthy ovat The comparatively rapid 
development of the embryo (six to seven days) is further favourable for a connected 
series of observations The lateness of the spawning period in 1886 was also fitted to 
* Op. cit., p. 99. 
+ Vide account of appearance of retained ova, Third Annual Report of Scottish Fishery Board, 1885, p. 62. 
VOL. XXXV. PART III. (No. 19), 6P 
