of the Fishery Board for Scotland. 
281 
stages of the unknown sinistral form, for comparison with the specimens 
from the East Coast. 
Now, on contrasting the young stages previously described, it is found 
that the three younger stages — varying from Tr2 to 7 5 mm. in spirit, 
from Ireland (the coast of Donegal) — have slightly smaller eyes, some- 
what longer opisthures, and better-marked pigment, — differences, how- 
ever, that may be due to the mode of preparation. The older form with the 
eye ou the ridge, on the other hand, closely corresponds with the examples 
from the East Coast. They all appear to belong to the same species.* 
In the Researches the next stage of the turbot was supposed to be that 
described on p. 846, and figured by Prof. Prince in PI. XIX. fig. 1, a form 
which has much of the aspect of a turbot, but it possesses otocystic spines, 
which Mr Holt's discovery shows are present in what he supposes to be the 
brill, and which hitherto we have not seen on the turbot. Mr Holt 
has made sections of these and finds that the great otic cartilage is thickened 
into a sort of knob at the points corresponding to the bases of the spines. 
Each has a slight basal cavity into which the epithelium lining the oto- 
cyst extends, but this exhibits no special sensory structure. Distal ly 
the knob of cartilage passes insensibly into a mass of undifferentiated 
mesoblastic cells, the whole forming a core of a hyaline ossific process. 
The latter is very brittle, so that its shape cannot readily be determined 
by the method of section ; but examination of entire examples shows that 
the spines are compressed somewhat in the manner of a pyramid. They 
are subequal in length, but the lower spines are somewhat broader and 
more blunt than the upper pair. He records the occurrence of a promi- 
nence in the position of the upper otocystic spine in a young turbot, but 
is not sure what it is, and similar thickenings have occasionally been seen 
here. The shape of these pelagic brill, moreover, may be more or less 
abnormal, since Mr Holt points out that all the young forms he procured 
off the west coast of Ireland were characteristically elongate. In this 
example the pigment-bars agree with those seen in the Irish specimens of 
brill ; the two otocystic spines are distinct, the dorsal curve of the head 
and its general appearance, and the comparative size of the eye, all lean 
to the type indicated by the early forms sent by Mr Holt. Moreover, Mr 
Collinge carefully calculated the rays of the dorsal and anal fins so as to 
check the observations already made, and it was found that there were at 
least 80 rays in the dorsal and 60 in the anal. In another young 
specimen procured by the 4 Garland ' on Smith Bank, off Caithness, the 
two otocystic spines were more prominent, especially when viewed from 
the dorsum (PI. XIV. fig. 14). The dorsal had 87 and the anal 62 rays. 
These somewhat abnormal brill are evidently much older than the 
doubtful form of 9*5 mm. with the eye on the ridge, as, for instance, may 
be seen from the condition of the caudal and other fins. Yet the right 
eye is either just visible from the left, or at anyrate is much less 
advanced towards the left than in the oldest stage of the unknown form, 
as figured in PI. XIV. fig. 11. This would indicate that the latter, in all 
probability, belongs to a smaller species. 
An examination of such small forms as I have been able to obtain 
gives the following results as regards the fin-rays : — In a young 
turbot 15 mm. long, captured on the 1st September 1891, and procured 
from the Plymouth Laboratory, the dorsal had 66 and the anal 48. The 
upper third of the right eye appears over the ridge, but the pupil looks 
chiefly to the right, or upwards and outwards. The dorsal is some 
distance behind the eye. The opercula are spinose. The pigment on the 
right side is profuse, and only a little less deep than on the left. 
An example 21 mm. in length, procured in the trawl on the 21st July 
* The excellent figures of Mr Holt will, when published, considerably aid future 
observers in the department. 
