Struciure and 0 economy of Whales. 43 p 
thefe may be named the elevator, depreffor, addudlor, and ab- 
ductor, and may be differed away from the others as diffindt 
mufcles. Befides thefe four going from the mufcles of the 
eyelid to the eye itfelf, there are two which are larger, and in- 
clofe the optic nerve with the plexus. As thefe pafs outwards 
they become broad, may in fome be divided into four, and 
are inferted into the fclerotic coat, almoft all round the eye, 
rather behind its tranfverfe axis. 
The two oblique mufcles are very long; they pafs through 
the mufcles of the eyelids, are continued on to the globe of 
the eye, between the two fets of ffcraigh t mufcles, and at 
their infertions are very broad ; a circumftance which gives 
great variation to the' motion of the eye. 
The fclerotic coat gives fhape to the eye, both externally 
and internally, as in other animals ; but the external ihape and 
that of the internal cavity are very diflimilar, arifing from 
the great difference in the thicknefs of this coat in different 
parts. The external figure is round, except that it is a little 
flattened forwards; but that of the cavity is far otherwife, . 
being made up of ledtions of various circles, being a little 
lengthened from the inner iide to the outer, a tranfverfe fedtion 
making a fhort ellipfis. 
In the Piked Whale the long axis is two inches and three- 
quarters, the fhort axis two inches and one-eighth. 
The pofterior part of the cavity is a tolerably regular curve, . 
anfwering to the difference in the two axifes ; but forwards, 
near the cornea, the fclerotic coat turns quickly in, to meet 
the cornea, which makes this part of the cavity extremely flat, 
and renders the diffance between the anterior part of the fcle- 
Vol. LXXVII. Q q q rotfe 
