134 REPORT—1840. 
subject had previously been, that young salmon hatched in the spring 
of any given season made their migration to the sea in the course of 
that same spring, that is, when they were only a few weeks old, and 
that they consequently bore no relationship to that other small fish 
commonly called the parr, which was known to inhabit our river waters 
during all seasons of the vear. Mr. Shaw, however, has proved that 
both those views are erroneous, and that the fry continue for about 
two years in the river, during which they are actually the parr, and are 
converted in the course of the second ensuing spring into smelts or 
young salmon, as usually recognized. The specimens exhibited by 
Mr, Wilson demonstrated the occurrence of that change. 
On the Organs of Sense in the Salmon. By Dr. Lizars. 
After demonstrating the structure of the skin, the author showed that 
the colour of the animal depended not merely on the rete mucosum, as 
in the dark varieties of the human race, but that the superficial fascia 
exerted a great influence, from its colour and the transparency of the 
dermis. The rete mucosum was a soft gelatinous layer, presenting a 
number of minute black points, which were very abundant in the dark, 
but few in the light parts of the skin. The superficial fascia bore the 
closest resemblance to the rete in the greater part of its extent; but in 
some situations it exhibited the appearance of adipose tissue. From 
the arrangement of the nerves, the skin appears far from being highly 
organized for the function of touch. The same remark applies to the 
tongue and the sense of taste ; first, from the state of the mucous mem- 
brane, and second, from the small size of the gustatory nerves. The 
organ of smell was very highly developed. It is contained in an 
elongated cavity placed in the upper and fore part of each side of the 
head, leading to each of which there are two apertures placed close 
together, the septum between them serving the purpose of a valve to 
the anterior, so that water could enter, but could not escape by it. 
Upon examining the posterior opening with the microscope and with 
bright sunshine, a number of minute white filaments, bifurcated at 
their extremity, were observed: they were supposed to be ciliz ; one 
or other of their minute extremities was seen bending and extending 
itself. On the inner wall of the cavity were twelve delicate folds 
of membrane, attached to a slight prominence, and receiving the 
filaments of the nerve of smell. He supposed the water, loaded with 
the odoriferous particles, to enter by the anterior orifice, flow be- 
tween the olfactory folds, impress the nerve, and escape by the pos- 
terior aperture ; the ciliz in the last producing the current in that 
direction. In the description of the eye, a peculiar thickening of the 
cornea was pointed out a short way from the circumference, and more 
extensive at the lower than at the upper part. The sclerotic coat he 
found very thin, single, and having a thick, strong layer of cartilage 
extending from near the cornea to within three or four lines of the 
optic nerve. The ciliary ligament is very soft and delicate. The 
