222 The Alligator and Its Allies 



the brain, though its further course could not 

 be followed; (2) a somewhat larger posteriorly 

 directed artery, oc, going to the muscles at the 

 occipital region of the skull; (3) a short laterally 

 directed stem, z\ The last-named branch, z', 

 in turn, leads in three directions: (a) to the collater- 

 alis colli artery through the connective x''; (b) 

 a short anteriorly directed vessel, e, that passes 

 into the skull, possibly to the ear, through the 

 large foramen that lies between the exoccipital and 

 quadrate bones; it gives off a small twig, q, to the 

 muscles in the region of the jaw articulation 

 (quadrate) ; (c) the main stem of the branch z 

 continues laterad and cephalad as one of the chief 

 arteries, z^, to the anterior region of the skull, 

 giving off a fairly wide branch, jm', to the large 

 jaw muscle, and then two branches, o' and o^ to 

 the lateral surface of the eyeball and socket; it 

 then anastomoses, just cephalad and laterad to the 

 eye, with the forward continuation, cm^ of the 

 corresponding main stem, cm, of the common 

 carotid, already mentioned. The vessel cm', 

 after almost meeting its fellow in the middle 

 line, passes cephalad and laterad across the 

 ventral surface of the eye to the union, above 

 mentioned, with the lateral branch, z^; at the 

 posterior-mesial border of the eye it gives off a 

 branch that divides into two twigs, one, o^, for 

 the posterior eye muscles, and one, e', to the 

 region of the ear and the top of the skull. 



