MAIVIMALS 



476 



Figs. 618 to 620. — Sutural Arrangements of the Lens in Placentals. 



Fig. 618.— The sutural 

 arrangements in a 

 lower Mammal (a rab- 

 bit), forming a transient 

 stage in the develop- 

 ment of the lens of 

 Primates. 



Fig. 619. — The general 

 sutural arrangements in 

 Primates. 



Fig. 620.— The anterior 

 surface of the lens in 

 Primates. 



in general, among Sanropsida the maximum tliickness is at the 

 equator ; in IMammaha the general scheme of the human capsule 

 is followed, but the thinning at the anterior pole which seems to be 

 associated with the formation of an anterior lenticonus during accom- 

 modation is peculiar to the Primates (Fincham, 1929) (Figs. 787 to 

 790). 



The differences in configuration in the ciliary body necessitate variations 

 in the arrangement of the zonular fibres (Figs. Q21-3).^ In Rodents with ciliary 

 processes prolonged onto the iris the zonular fibres arise from their posterior 

 halves only ; in Ungulates they arise from the posterior two-thirds of the processes 

 but hug them anteriorly to their apex. In both ca.ses they run along the floors 

 of each valley and the sides of the adjoining processes to proceed in discrete bands 

 towards the equator of the lens. In Carnivora, however, with their greater 



Figs. 621 to 623. — The Zonular Fibres of Placentals. 



Fig. 



621. — An Ungulate Fig. 622. — A Carnivore Fig. 623. — A Primate 



(pig). (cat). (monkey). 



The zoiiular fibres are outlined in continuous lines, the major ciliary 

 processes in dotted lines, c, cornea ; /, iris ; /, lens ; s, sclera, p indicates 

 the smaller perpendicular bundles of fibres associated with the minor ciliary 

 processes (from Kallmann and Walls). 



1 For the comparative anatomy of the zonule, see particularly Aeby (1882), 

 Kahmann (1930), Teulieres and Beauvieux (1931), Troncoso (1942), Wislocki (1952), 

 Fukamachi (1953). 



