6 Mr. T. Smith on the Muscular Structure and Functions 



direct ocular observation. Certain peculiarities, however, 

 which have not been mentioned by anatomical writers, are 

 sufficiently distinct to be seen by the help of the microscope, 

 or even with the naked eye, in a favourable light. If the whole 

 vitreous humour, and lens imbedded in it, are taken out of the 

 eyeball, by cautiously separating the hyaloid membrane from 

 its connexions with the parts around the iris, the lens in its 

 capsule is seen surrounded by a beautiful radiated circle or 

 zone, which has been generally but erroneously described as 

 merely the marks left by the ciliary processes on the hyaloid 

 membrane. Even the celebrated Cuvier speaks of it as nothing 

 more- Dr. Knox of Edinburgh corrects this mistake. The 

 zone around the capsule exhibits, he says, " a very complicated 

 structure. On that part of the hyaloid membrane on which 

 the ciliary processes rest, we find an equal number of folds or 

 laminae, which projecting outwards, are dove-tailed, as it were, 

 with the ciliary processes. These membranous folds are vas- 

 cular, the vessels pass in great numbers from the ciliary pro- 

 cesses to them, and these vessels, together with the dove-tail- 

 ing of the two sets of processes, form, as every anatomist ought 

 to know, the bond of union between the choroid and hyaloid 

 membranes, which otherwise would have no connexion with 

 each other*." The radii, which are here termed membranous 

 folds, unite together in a circular ring around and close to the 

 capsule, and even seem to spread over the circumference of the 

 capsule itself, giving it a notched appearance, noticed by M. 

 Cloquet, and forming a pretty broad belt all round the capsule. 

 To the naked eye, the radii of the zone, when washed free from 

 the black paint which generally adheres to them, the ring in 

 which they unite, and the belt which I have described as sur- 

 rounding the capsule, have a remarkable resemblance to the 

 muscular fibre of the haddock or of the whiting; and when 

 they are viewed through a powerful microscope, the fibrous 

 structure is seen in the most distinct manner along the ridges 

 of the radii and across the ring and belt. 



If we divide the eyeball of any of the larger quadrupeds into 

 two nearly equal parts, by a section of the sclerotic coat and 

 vitreous humour parallel to the plane of the iris, and invert 

 the section containing the lens, that body will be seen through 

 the remaining part of the vitreous humour surrounded by a 

 radiated circle, consisting of the zone of the hyaloid membrane 

 above mentioned in conjunction with the ciliary processes of 

 the choroid coat, and forming what has been termed the ciliary 

 body, — the following particulars respecting which deserve at- 



* Vide Translation of Cloquet'* Anatomy, p. 552. 



