SKATE. 
91 
fish are, from the snout to the mouth one part to three and 
three quarters of its breadth, and less than one fifth of its 
whole length. The males, like the Sharks, are distinguished 
hy claspers attached to the ventral fins, hut they are larger 
in proportion to the bulk of the fish. The colour of the 
upper parts is dusky or grey, variously mottled; and in the 
younger examples the tail is marked with rings of colour. It 
often reaches the weight of a hundred pounds, and would 
scarcely be thought extraordinary if of double that magnitude. 
I have thought it proper, in my introductory remarks on 
the newly-named genus. Bafts, to direct attention to the 
conspicuous mucous glands which characterize this division 
of the great family of Plagiostomes ; and TNIonro has thought 
them worthy of a separate chapter in his work on the 
“Physiology of Fishes.” “In the Skate,” says he, “numerous 
orifices, placed pretty regularly over the surface, have been 
observed by Steno to discharge the slimy matter. With 
respect to these last I have remarked some memorable circum- 
stances. First, I have discovered one very elegant serpentine 
canal between the skin and muscles, at the sides of the five 
apertures into the gills. Further forwards it surrounds the 
nostrils, then it passes from the under to the upper jiart of 
the upper jaw, where it runs backwards as far as the eyes. 
From the principal part of this duct in the under side or 
belly of the fish, there are not above six or eight outlets; 
but from the upper part near the eyes there are upwards of 
thirty small ducts sent off, which open upon the surface of 
the skin. The liquor discharged from these has nearly the 
same degree of viscidity as the synovia in man. But besides 
the very picturesque duct I have been describing, I have 
remarked on each side of the fish, a little further forwards 
than the foremost of the five breathing holes, a central part, 
from which a prodigious number of ducts issue, to terminate 
on almost the whole surface of the skin, excepting only the 
snout or upper jaw. At these centres all the ducts are shut; 
and in their course they have no communication with each 
other. In these two central parts, or on the beginning of 
the mucous ducts, a pair of nerves, nearly as large as the 
optic, terminate; and, which is a curious circumstance with 
respect to them, they are white and opaque in their course 
