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 1 . The last-named branch, z 1 , 

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

 alis colli artery through the connective x 1 ; (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 2 , to the anterior region of the skull, 

 giving off a fairly wide branch, jm 1 , to the large 

 jaw muscle, and then two branches, o 1 and o 2 , to 

 the lateral surface of the eyeball and socket; it 

 then anastomoses, just cephalad and laterad to the 

 eye, with the forward continuation, cm 1 , of the 

 corresponding main stem, cm, of the common 

 carotid, already mentioned. The vessel cm 1 , 

 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 2 ; at the 

 posterior-mesial border of the eye it gives off a 

 branch that divides into two twigs, one, o 3 , for 

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

 region of the ear and the top of the skull. 



