140 Peculiar Structure in the Eyes of Fishes. 



at present, direct and incontestible proof is wanting. I may 

 observe that in the eye of the pike, a predaeeous fish, posses- 

 sing remarkable quickness of vision, the pyriform body is not 

 only relatively, but absolutely larger than in a cod fish, great- 

 ly exceeding it in weight. 



That the existence of this body is as yet unknown, in Eng- 

 land at least, is I think borne out by the fact, that the learned 

 Professor of Comparative Anatomy at the Royal College of 

 Surgeons, Mr. Owen ; and Mr. Yarrell, so well known by his 

 beautiful work on the ichthyology of Great Britain ; were both 

 unacquainted with the circumstance when I mentioned it to 

 them. 



In a number of the American Journal of Science and Arts, 

 will be found a somewhat similar account of a muscle, disco- 

 vered in the eye of the streaked bass, (Perca nobilis vel Mit- 

 chellii), by Mr. W. Clay Wallace, surgeon to the New York 

 institution for the blind. This gentleman did me the favor 

 to send me over, about twelve months since, his paper pub- 

 lished in that journal. From the circumstance of my not be- 

 ing aware of being personally acquainted with Mr. Wallace, 

 I cannot help suspecting that he is one of the Americans to 

 whom the observations made by me, were imparted at the 

 ophthalmic hospital, some years ago. I beg, however, to re- 

 turn him my thanks for much new and interesting matter, 

 which has been added by him. 



The following quotation from Mr. Wallace's paper, gives 

 all that he has said relative to this body. 



" At the inferior axis of the crystalline lens, (in the Perca 

 nobilis), and attached to its capsule, is a small triangular bo- 

 dy, having its inner surface covered with pigmentum nigrum. 

 It adheres to a cord placed at the divided portion of the re- 

 tina. It passes through a loop in the iris, and is inserted 

 into the vitreous humour, behind the crystalline. When the 

 portion, a part of which passes through the loop, is brought 

 into action, the vitreous humour is drawn forwards, and the 

 lens is pushed before it. When the other portion acts, the 

 lens is drawn backwards. 



" Cuvier states that ' in a great number of fishes, there is a 

 falciform ligament which passes through a slit in the retina, 

 and penetrates the vitreous humour.' * It contains blood-ves- 

 sels and nerves, and is attached to the capsule of the crystal- 

 line lens, at its inferior surface, sometimes by a simple ele- 

 vation, or by a fold, a little more opaque ; at other times by 

 means of a grain or tubercle, transparent and harder than the 

 vitreous humour in which it is placed.' Cuvier has ascribed 

 no function to what is described. Jurin named it the gan- 



