Fig. 105 — The teleost eye and its accommodation. 



In each drawing (except e), the temporal side of the eye is on the left, the nasal on the right. 



a, generalized teleost eye in horizontal optical section. After Franz, av- anterior surface of 

 vitreous; c- cornea (cf. Fig. 67, p. 159, for detailed labelling of its three portions) ; eg- chorioid 

 'gland'; cm- ciliary muscle (tensor chorioideee' ) ; fp- falciform process; x- iris; /- lens; on- 

 optic nerve; re- retina; rl- retraaor lentis muscle; sc- scleral cartilage; so- scleral ossicle 

 (cf. Fig. 130b, p. 380); vc- vitreous cleft; z- zonule, b, left eye of Blennius sanguinolentts 

 from above, in relaxation, x 3. After Beer, c, same as b; in full accommodation; note 

 temporad duction of lens accompanying retraaion. d, the adjustment of a teleost eye for 

 an approaching object (relaxation of the retractor muscle, and return of lens forward to its 

 rest position); o-o'-o"- successive positions of objea; l-l'-l"- successive positions of relaxing 

 lens; i-i'-i"- successive locations of retinal image, in the absence of a fovea which would call 

 for fixative rotation of the eye. e, cross seaion of optic nerve of Serranus cabrilla, showing 

 edgewise-folded ribbon structure characteristic of many teleosts. From Franz, after Studnicka. 

 f, eye of Serranus cabrilla in relaxation, showing anterior aphakic space common in teleosts 

 and often associated with a fovea temporalis. Modified from Beer, g, diagrammatic frontal 

 section of teleost eye, showing mechanism of accommodation. Based on a figure of Meader, 

 /- embryonic fissure; /- lens; n- motor nerve in falciform process; r- retraaor lentis muscle; 

 s- suspensory ligament. 



261 



