682 MAMMALS 



bundle form a fan plastered against the face of a major process — one 

 fan against each face. These fibers insert anterior to the lens equator 

 (Fig. 197c). Other fibers arise from the ciliary epithelium alongside 

 the roots of the major processes, and pass along their faces and across 

 the circumlental space to insert posterior to the lens equator. Again 

 there is no canal of Hannover; but the insertions of the fibers are not 

 uniformly scattered around the lens, but are grouped at a number of 

 discrete places — twice the number of the major processes. There is thus 

 an even more free communication (between the bundles) from the 

 anterior chamber to the posterior than in the case of ungulates etc. 

 The anterior surface of the vitreous is plicated where it bulges forward 

 a bit into each ciliary valley, and its pressure against the posterior zonule 

 fibers keeps them bowed; but the anterior fibers take straight courses. 

 The periphery of the lens is scalloped by the discontinuous attachment 

 of the zonule. 



The minor processes also have sheets of zonule fibers against their 

 flat surfaces. These arise perpendicularly from the anterior part of the 

 ciliary body and pass to the posterior insertion-zone on the lens. The 

 insertions are in meridians intermediate between those of the major fans 

 (Fig. 197b). All zonule fibers thus lie against ciliary-process surfaces. 

 A frontal section through the ciliary body shows no fiber cross-sections 

 on the floors of the valleys or in the open spaces of the valleys them- 

 selves — a great contrast with the ungulates and lower placentals. 



According to Kahmann, the primate zonule exhibits still another 

 fundamental plan: Fibers from the greater part of the orbiculus pass 

 only to the anterior lens capsule (forming the anterior leaf) , and others 

 from near the posterior ends of the ciliary processes pass only to the 

 posterior capsule, forming a posterior leaf. These two masses of fibers 

 thus cross each other in the coronal zone (the writer is not at all con- 

 vinced of this). A few of the fibers with orbicular origins insert at the 

 lens equator, and thus travel across the otherwise 'empty' canal of Han- 

 nover. Still other fibers, originating far anteriorly, pass to the posterior 

 capsule and thus compare with the 'perpendicular' fans of the cat; but 

 in man there are no regular minor ciliary processes for them to cling to. 

 From these descriptions, it will be seen that where accommodation is 

 considerable (carnivores; and, to a much greater extent, primates*), the 

 zonule fibers which will be most relaxed by the contraction of the ciliary 



*The zonules of the squirrels should receive as careful a study as Kahmann has given those 

 of the other strongly-accommodating mammals. 



