70 Part LIT. —Twenty-fourth Annual Report 
gularly convex. One end is subtruncate, but the other is broadly rounded. 
The earstones of a considerable number of long rough dabs have been 
examined, and it has been noticed that though the larger examples 
retained their characteristic shape there was some variation in the propor- 
tion of their sizes to the length of fishes they belonged to. The two 
largest of the fishes among the number selected for this paper measured 
respectively 370mm. and 317mm. in length, their earstones—represented 
by figs. 7 and 8—are almost identical in size, and measured about 7°5mm. 
and 5mm. in length aud width. It has been observed that the length 
of the earstones of most of the Pleuronectids examined are shorter in pro- 
portion to the length of the fish than those of the more typical Gadoids. 
The earstones of the two fishes mentioned above averaged, roughly, about 
the one forty-fifth or forty-sixth part of the average length of the fishes. 
It has also been noticed that where there is an increase in the width of 
the otoliths there is to some extent a corresponding decrease in the length. 
In the annexed Table the length of other five examples of long rough 
dabs are given, with the lengths of their earstones:— 
| 
| Earstones. 
Figure on the Length of the 
Plate. (iii. A.) Fish. | 
Length. Depth. 
: : One 4°5mm. and 
9 10 inches. About 6‘5mm. one One 
10 SAGs Ag eeiinuin, About 3°8mm. 
11 aes. » 4'8mm. 5) | OL OMIM 
12 om ye | Fully 30mm. 5 ua 
13 Sass | About 25mm. so 20mm 
The earstones of the smaller fishes become more and more rotundate as 
the length of the fishes decrease. 
Genus Bothus. 
Bothus maximus (Linn.). The Turbot. Pl. i.3., fig. 33. 
The earstones represented by fig, 33 were from a turbot of about the 
average size (about 20 inches in length), One of them, which is barely 
6mm. over all, in its general outline is very like one of those of the large 
halibut already referred to (fig. 1, pl. iii. a.), but much smaller, and it is 
fully 4mm. in width; the other earstone, which is nearly of the same 
length as the first, but about 45mm. in depth (or width), has a somewhat 
different form, and differs also in having the entire margin distinctly 
crenulated. This difference between these two earstones may be only 
accidental, but the otoliths of another fish to be presently described show 
that such variation may be normal. Whether it beso in the present case, 
however, can only be ascertained by the examination of several specimens 
of different sizes, but not the very young, where variations of this kind 
tend to disappear. 
The earstones of the brill, Bothus rhombus, are not represented among 
the specimens photographed, but they appear to resemble those of the 
turbot. 
