464 THE EYE IN EVOLUTION 



rudimentary or vestigial. In Rodents this ligament is made up of 

 innumerable short fibres at the opening of the cleft, which itself is 

 empty (Figs. 583, 591, 596) ; in Ungulates (such as the horse, ox, pig 

 and sheep) the strands over the opening of the cleft are stout and well 

 developed, like the girders of a bridge spanning the ciliary cleft, while 

 the body of the cleft is filled by a close irregular meshwork of fine fibres 

 appearing as spongy tissue (Figs. 584, 592) ; in Garni vora (such as 

 the dog and cat) the more anterior strands supporting the root of the 

 iris are thin and delicate like the cables of a suspension bridge, while 

 the depth of the cleft is filled with fine threads running a fan-like 

 course with no resemblance to spongy tissue (Figs. 585, 593, 597) ; 



Figs. 591 to 594. — The Angle of the Anterior Chamber of Placentals. 



As seen gonioscopically, showing the configuration of the pectinate ligament 

 (from drawings from Troncoso). 



■^4nmy^^»ti:^^,^ 



Fig. 591.— Rabbit. Fn;. .V.)l'. I'm. Fig. 593 



in the Pinnipedes (seals) the anterior strands are particularly stout. 

 In the Primates (man) the pectinate ligament is discernible until the 

 6th month of foetal life (Collins, 1899 ; Seefelder, 1910), but owing 

 to its subsequent atrophy it can hardly be said to exist in the adult, 

 the support of the lens being more adequately undertaken by the dense 

 muscular and trabecular tissue of the ciliary body (Figs. 586, 594). 



This interesting and important region has received a considerable amount 

 of attention. The first to give an adequate description with illustrations was 

 Murray (1780) at Uppsala who called the cleft at the angle of the anterior 

 chamber of the ox the ciliary canal. In the following year, Felix Fontana (1781), 

 the anatomist of Pisa and Florence, gave a description of the same region and 

 since then the extensions of the anterior chamber into the ciliary region of 

 Mammals have variously been called Fontana's spaces or canals. Shortly there- 

 after Kieser (1804) of Gottingen pointed out that such structures did not exist 

 in man. Subsequently Hueck (1839) of Dorj^at, studying the cow's eye, described 

 the teeth-like structures stretching over Fontana's spaces from the root of the 

 iris to the sclero -corneal junction as the pectinate ligament (pecten, a comb), an 

 appropriately descriptive term ; since then it has been called by many names — 

 the suspensory ligament of the iris, the iVis pillars, and so on (Fig. 595). 



Over the last centviry and a half much study has been given to the ciliary 

 region of the mammalian eye — most of it histological.^ More recently a better 

 perspective has been put on the anatomical arrangements by the gonioscopic 



1 Flamming (1868), Iwanoff and Rollett (1869), Angelucci (1881), Dostoiewsky 

 (1886), Virchow (1886-1910), Rochon-Duvigneaud (1892-93), Collins (1899), Asayama 

 (1901) uber (1901), Seefelder and Wolfram (1906), Henderson (1908-50), Rohen 



(1953- .. , md de Toledo Piza (1955). 



