146 The Alligator and Its Allies 
lis.’ This reservoir is of irregular form and opens 
forwards into the base of the nasal cavity proper. 
The third type of gland mentioned above, the 
conjunctival, is found on the lower eyelid where 
the conjunctiva passes from the lid to the eyeball. 
The gland is of a “‘scattered acinose’”’ type. 
The usual muscles of the eyeball are found in 
the Crocodilia. The four rectus and two oblique 
muscles have about the usual arrangement and are 
attached to the eyeball by very short aponeuroses. 
The retractor oculi muscle is only weakly developed. 
It consists of two separate bundles which, lying 
behind the optic nerve, arise from the forward bony 
wall of the socket and are inserted on the sclera 
very near the optic nerve. 
The eyeball consists of the usual layers, includ- 
ing, as might be expected from the nocturnal habits 
of the Crocodilia, a typical tapetum lucidum. 
| In the sclera, instead of the bony ring common 
to the saurians, is found a well-developed cartilage 
covered with the fibrous layer of the sclera; the 
fibers of this layer are arranged into two more or 
less distinct layers. 
While not worked out in detail the cornea consists 
of the usual five layers. 
"In the iris the musculature is less developed than 
in the birds; Bronn thinks this may be compen- 
sated for by the greater development of the 
“vascular structures.” 
The pupil is a vertical slit. 
