362 THE LENS, BY PROFESSOR BABUCHIX. 



flatter and more slender at their centre than at their extremi- 

 ties (fig. 372 A). Their curvature alters as they approximate 

 the axis. The outer ones are straight, whilst those situated 

 more internally become more and more S-shaped, till they are 

 ultimately so much arched that both their anterior and posterior 

 extremities bend inwards towards the pole. In proportion as 

 the fibres approximate the axis they very gradually become 

 longer, in consequence of which the fibres of each successive 

 more deeply situated layer projects somewhat beyond the 

 supeijacent ones, so that the ends of these last, still adhering 

 to the anterior and posterior walls of the capsule, cover one 

 another like the tiles of a roof. 



But these characters refer only to the fibres of the several 

 peripheric layers of the lens. The extremities of the remaining 

 fibres, which belong rather to the inner layers of the lens, pass 

 to the poles and axis, and meet here with the extremities of 

 those fibres which come from the opposite parts of the lens. 



This junction varies in different animals. It is most simple 

 in some Fishes arid Amphibia, as in the Cod (Brewster), Triton 

 (Harting), Salamander (Harley), Frog (Becker), and in Birds, 

 where the fibres of the lens belonging to one and the same 

 layer begin from the asquator, gradually become more slender 

 and, like the intervening spaces of the meridians of the earth, 

 meet one another with pointed extremities at one point of the 

 axis of the lens. In some Fishes, as for example in the Torpedo, 

 the posterior extremities of the fibres also join or meet in the 

 axis, whilst the anterior ones of each layer form a raphe by 

 their apposition, which with low powers appears as a straight 

 line on the anterior surface of the lens, at right angles to 

 the axis, from which the fibres run in a radiating manner 

 towards the sequator. And inasmuch as the raphe of the 

 successive internal layers likewise forms straight lines with 

 gradual shortening towards the centre of the lens, it may 

 be said that in these cases the anterior extremities of the 

 fibres of the lens of all the layers meet in one (otherwise very 

 irregular) plane which perhaps has the form of a triangle, the 

 slightly arched base of which is turned towards the anterior 

 surface of the lens, whilst its vertex is lost in the nucleus of 

 the lens. 



