THE EYE. 



385 



arc of 60°. Now, the tubes arising from the middle of the 

 anterior " star" extend, on the posterior aspect, only as far as 

 the extremities of the three rays; and, on the other hand, 

 those commencing from the posterior pole do not reach the 

 middle of the anterior. Similar conditions obtain in all the 

 tubes situated between these two points, so that none of them 

 reach entirely round; and all the tubes in a layer are of 

 equal length. Now precisely the same thing also exists in the 

 " nucleus" of the lens in the adult, whilst in the superficial 

 lamella, and on the surface itself, we observe a more com- 

 plex " star," with from nine to sixteen rays of various 



Fig. 307. 



lengths and rarely quite uniform, among which, however, 

 three principal rays may be distinguished. The course of the 

 fibres is consequently rendered more complex, and the rather 

 so, because fibres attached to the sides of the rays converge in 

 an arched manner, so that the latter appear, as it were, 

 feathered, or form whirls {vortices lentis); but, notwithstanding 

 this, the course of the fibres remains essentially the same in 

 all respects as that above described, inasmuch as in this case 

 also the anterior and posterior M stars" do not correspond 

 with each other, and no fibre extends from the one pole to 

 the other. In the " stars" the substance of the lens is not 

 formed of tubes as elsewhere, but is in part finely granular, in 

 part homogeneous; and consequently, since the " stars" in- 

 volve all the layers, three or more, vertical, non-fibrous lamellae 



Fig. 307. Lens of the adult, after Arnold, to show the " star." 1, anterior aspect ; 

 2, posterior. 



ii. 25 



