OF THE SPERM WHALE. 
117 
round. They may be termed the dilatores of the eyelids, 
and before they reach their insertion give off the external 
straight muscles, which are small and inserted into 
the sclerotic coat before the transverse axis of the eye ; 
these may be named the elevator, depressor, adductor, 
and abductor, and they may be dissected away from the 
others as distinct muscles. Besides these four, going 
from the muscles of the eyelids to the eye itself, there 
are two which are larger and enclose the optic nerve 
with the plexus. As these pass outwards they become 
broad — may in some be divided into four— and are 
inserted into the sclerotic coat almost all round the eye, 
rather behind its transverse axis. The two oblique 
muscles are very long ; they pass through the muscles of 
the eyelids, are continued on to the globe of the eye 
between the two sets of straight muscles, and at their 
insertion are very broad, a circumstance which gives great 
variation to the motion of the eye. The sclerotic coat 
gives shape to the eye both externally and internally as 
in other animals ; but the external shape and that of 
the internal cavity are very dissimilar, arising from the 
great difference in the thickness 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 
otherwise, being made up of sections of various circles, 
being a little lengthened from the inner side to the 
outer— a transverse section making a short ellipsis. In 
the piked whale the long axis is two inches and three 
quarters— the short axis is two inches and one eighth. 
The sclerotic coat becomes thinner as it approaches to 
