618 



REPTILES 



The ciliary body increases gradually in thickness from behind for- 

 wards, from near-equality with the chorioid to about twice this value. 

 Its base-plate and epithelium do not, however, diverge widely from the 

 sclera, so that only a small amount of spongy tissue lies between (Fig. 

 178; contrast Fig. 191, p. 645). Osawa to the contrary, there are no 

 ciliary folds or processes — the inner surface of the broad ciliary body is 

 perfectly smooth, which seems an important point in agreement with the 

 lizards. Where the ciliary body joins the iris, there is a sharp 'corner' or 



The anterior segment of Sphenodon punctatum. x 12. 

 cm- ciliary muscle (anterior, circumferential fibers show as 

 a group of dots beneath the canal of Schlemm); co- con- 

 junctiva; cs- canal of Schlemm (containing nerve, shown in 

 black); /- lens; ot- ora terminalis; r- ringwulst; sc- scleral 

 cartilage; so- scleral ossicles; i- zonule. 



annular ridge, from the crest of which a delicate, elastic, radially fibrous 

 cuticular membrane — actually, the anteriormost 'leaf of the zonule — 

 passes straight to the posterior surface of the iris which it intersects at 

 about one-third of the way from iris root to pupil. Here it is as firmly 

 fused with the iris as with the lens capsule; and, if the lens and iris are 

 separated (in preserved eyes, at least), it remains attached to the iris 

 rather than to the lens. The zone of the iris thus bridged by this mem- 

 brane has a rugose posterior surface on which the low, undulant folds 



