ACCOMMODATION IN SAUROPSIDA 



277 



whose elements are radially disposed and thus admirably oriented for 

 their service as architectural columns, transmitting the radial stress of 

 the ciliary processes directly to the spherical heart of the lens. Thd 

 annular pad has no optical function whatever, for the iris shields it 

 and the image-forming light beam is confined to the more onion-like 

 nuclear portion of the lens. Like the softness of the lens in Sauropsida, 

 the thickness of the annular pad, as might be expected, goes with activity 



Fig. 110 — Anterior segment of left eye of a turtle {Emys orbicularis'), seen from behind, 

 showing junction of ciliary processes with lens capsule (characteristic of sauropsidans — con- 

 trast Fig. 44, p. 115). X 13. After Konig. 



/- unclosed portion of embryonic fissure; /- lens; o- orbiculus ciliaris; p- ciliary processes; 



r- sensory retina. 



of the ciliary muscles, in its variation from species to species. It is thick- 

 est of all in the chameleons. 



The ciliary muscles in birds and lizards have the same location as 

 those of non-lacertilian reptiles, but are more complicated, as is explained 

 below. The fibers of sauropsidan ciliary muscles are all meridional except 

 in a very few species, and have their origin in the inner layers of the 

 cornea at its margin. Their insertions are not into the chorioid, as in the 

 Ichthyopsida, but are scattered along the orbiculus ciliaris much as in the 



