STING KAY. 
133 
nineteen inches j the snout short, thin, and a little turned up; 
from it to the eye three inches and a half; the eye rather 
small, and prominent; spiracles large, and passing forward under 
the eye. At about the middle of the body it is much raised, 
and from that part it slopes both forwards and behind; the 
widest part at about six inches and a half from the snout, and 
consequently before the middle; ventral fins nearly square pos- 
teriorly. The tail thick and round from its origin to the place 
of the spine, and from thence slender. Root of the spine five 
inches and a half from the origin of the tail; the spine five 
inches long, lying lengthwise; moderately sharp, grooved in 
several lines, with a keel below, armed along each side with 
a close-placed row of reversed points. A deep depression 
along the middle of the back of the tail from its origin up- 
wards— there obsolete; two others on each side of the root of 
the spine, passing up to the cross bones not far behind the 
eyes; which lines, although fainter than the middle line below, 
are more strongly marked above. The skin smooth; mouth and 
teeth small. In one example the general colour was a dark 
red, in another dusky yellow. 
It is a wise provision in the oeconomy of nature, that when 
the dart has become blunted or otherwise useless, provision is 
made for its being restored, by a loosening of its root of 
attachment, when it drops off, and is replaced by a new one. 
Whether this is done periodically, or at irregular intervals, is 
not known; but it sometimes happens that the newly-formed 
spear is well advanced in growth before its predecessor is 
thrown off, and an instance of this sort enables us to remark 
that both had their origin from the same root or gland. The 
older spear was the longer, being seven inches long^ in a fish 
the extreme length of which was three feet, hanging rather 
loosely; while the new, which protruded under the other, 
closely adhered for half an inch, and was of softer consistence 
near its root. Professor Owen refers to Agassiz, as pointing 
out the close resemblance of the microscopic structure of the 
bone of this spine or dart, and the dentine of the teeth of 
the same fishes; they are both hardened by an outer layer of 
modified dentine, but as hard as enamel. 
Mr. Dillwyn (Fauna of Swansea,) mentions an instance of 
the occurrence of two spines in a Sting Ray caught near 
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