470 Prof, Reid on the Vogmarus Islandicus. 
numerous small fibrous septa sent inwards from the mner surface 
of the skin, and to the inner surface of the skin. Bundles of these 
muscular fibres may be seen at some parts of the abdominal walls 
running between the skin and aponeurotic lining of the abdomen 
separated by numerous aponeurotic septa. Septaare also sent in- 
wards from the inner surface of the skin to the interneural spines, 
separating each pair of muscles which move the dorsal fin rays, 
and numerous small septa are also at some places sent inwards 
from the skin among the muscular bundles filling up the fibrous 
sheaths. The strong central partition, and the fibrous prolon- 
gations inwards of the skin impart an amount of strength to the 
whole body, and afford an extent of firm attachments to the 
muscular bundles, which the imperfectly developed neuro-skele- 
ton could not of itself have supplied. Of the three uppermost 
muscular sheaths, the lower one, immediately behind the occiput, 
is very much wider than the other two. Opposite the ninth ver- 
tebra they were nearly equal in width and measured each about 
f;ths of an inch, but on proceeding backwards the upper and 
lower diminished in width much more rapidly than the middle, 
so that opposite the thirty-sixth vertebra while the middle mea- 
sured ;5ths of an inch in width, the lower measured only ; ths 
and the upper ;3,ths of an inch. The upper muscular sheath 
lies over the upper extremities of the spinous processes of the 
vertebra, and the portion of the lower extremities of the inter- 
neural spines and of the muscles of the dorsal fin rays interposed 
between these. Of the two undermost muscular sheaths, or those. 
placed below the lateral line of the body, the one next the spine 
is much narrower than the lower. 
The microscopic examination of the tissues of this animal fur- 
nished some interesting results. 
Skin.—The skin is thin, being about jth of an inch in thieck- 
ness, is in close contact with the subjacent muscular bundles, 
and is destitute of scales. It may be divided into two parts—an 
epidermic portion and the chorion or true skin. The more ex- 
ternal of these, or the epidermic portion, may also be subdivided 
into two parts. One of these is composed of thin, narrow and 
elongated fibres (fig. 2), upon the presence of which the bright 
silver colour of the skin depends. These fibres are arranged in 
bundles, are firmly agglutinated together, those of the same 
bundle run parallel or nearly so to each other, and have one of 
their flat surfaces looking outwards, and the other towards the 
subjacent layer of the skin. A layer of similar fibres covers the 
anterior surface of the iris, giving it a bright silvery colour. It is 
very difficult to, separate these fibres from each other, and m 
attempting this they were generally broken into fragments of 
greater or less size. Those of the iris were not so firmly agglu- 
Se 
