‘878 Prof. J. C. Schiddte on the Development of 
Fig. 4. Section of the upper portion of the tooth of Polypterus, from 
Agassiz, showing the cap of enamel, a. 
Fig. 5. Section of poping of maxilla of Rhizodopsis, much enlarged, ex- 
hibiting the bony pillars supporting the teeth: a a, bony pillars ; 
6, b, teeth in an abraded condition, the enamel having at disap 
peared, and, in some instances, portions of the dentine. 
XLVI.—On the Development of the Position of the Eyes in 
Pleuronectide. By Prof. J. C. Scuiépre. Communi- 
cated by C. A. Gosch, Esq. 
(THE question of the asymmetry of Pleuronectide: has of late 
attracted so much attention, and we possess so few reliable 
descriptions of the appearances presented by very young spe- 
cimens (whereby alone that question can be solved), that the 
following observations on this subject by Prof. Schiédte will 
doubtless be found highly interesting, not only to ichthyolo- 
gists, but to zoologists generally. I wish particularly to draw 
attention to two of his results, now established by actual exa- 
mination of successive stages of development of the same spe- 
cies, viz. :—first, that the eye of the blind side glides across the 
head in front of the dorsal fin without ever disappearing from 
view, and, when arrived on the other side of the dorsal fin and 
clear of it, recedes backward alongside the fin, which does not, 
as supposed by some, prolong itself after the passage of the eye; 
and, secondly, that this shifting of place is a very slow process, 
for which, in all probability, preparation is made in the foetus. 
Prof. Schiddte’s article is destined shortly to appear in the 
fifth volume of the ‘ Naturhistorisk Tidsskrift;’ but having 
been favoured by the author with a separate impression, I am 
enabled already to present it to the readers of the ‘ Annals.’ 
The author begins by describing the specimens which form 
the principal material of his treatise in the following manner. | 
On examining a young specimen of Rhombus barbatus which 
lies before me, and which measures 18 millims. in length 
from the apex of the closed lower jaw to the extreme end of 
the caudal fin, I observe that the ramifications of the mucipa- 
rous canal on the head are not traceable; but the outline of the 
parts of the mouth, of the preoperculum, and the opercula are 
clearly perceptible through the skin, as well as the layers of 
the muscles, particularly of the great masseter on the right 
side. The left eye stands very nearly opposite to the middle of 
the upper jawbone. The right eye is placed at the top of the 
head, in front of the dorsal fin, but so much inclined to the 
left, that only one-third of its surface is visible when the fish 
