EYE OF THE ENGLISH SPARROW 

 THE NERVE SUPPLY TO THE EYE 



381 



The nerve supply to the eye and its accessory parts is derived 

 from five of the cranial nerves — the optic, oculoziiotor, trochlear, 

 abducens, and trigeminus. 



Fig. 17 Posterior view of the right eye of the sparrow, [showing the venous 

 supply to the eyeball and accessory structures. EF, external facial; Hg, Har- 

 den an gland; A'' Op, optic nerve; Oh i, inferior oblique; 06s, superior oblique; 

 01, infra-orbital; OpAI, internal ophthalmic artery; OpT, ophthalmotemporal 

 vein; Op V, ophthalmic vein; P, point where vein from pecten pierces the sclera; 

 P inf, infrapalpebral muscle; Py, pyramidalis muscle; qu, quadratus; Rex, 

 external rectus; R inf, inferior rectus; R inf, internal rectus ;^/2s, superior rectus. 

 X 10. 



• Figure 18, a ventral view of these nerves, shows their origin 

 and some of their distribution. The optic nerve (on) is very 

 short and thick. After leaving the chiasma (ch), it is directed 

 outward and forward and runs straight to the eyeball. This 



THE JOURNAL OP MORPHOLOGY, VOL. 31, NO. 3 



