of the Anatomy of the Squalus Maximus. 233 



colour of an amalgam of silver broken into small portions. 

 There are ciliary processes, not common to fishes in general ; 

 they are about one-third of an inch in extent, and slightly 

 projecting ; they are lined with a black pigment. 



The vitreous humour is unattached to the choroid coat ; it 

 is inclosed \n strong cells, and the crystalline lens, which is 

 spherical and one inch in diameter, is imbedded in it for two- 

 thirds of its substance. In the Tetrodon Mola, which, as well 

 as the Squalus Maximus, in common language has been called 

 the Sun-iish, the vitreous humour has a firm attachment to a 

 groove in the choroid coat one-twelfth of an inch in breadth, 

 extending from the entrance of the optic nerve to the termina- 

 tion of the retina, in the shortest line from the one to the other, 

 and there are no ciliary processes; two such remarkable dif- 

 ferences in eyes of nearly the same size, appeared to be de- 

 serving of being noticed. 



The cartilage upon which the ball of the eye rests is at- 

 tached to the bottom of the orbit, and is seven inches and a half 

 long; its stem is a flattened cylinder, five-eighths of an inch in 

 diameter ; it terminates in a broad concave surface in a trans- 

 verse direction adapted to the bottom of the ball of the eye, 

 and is connected to the sclerotic coat by a ligament long 

 enough to admit of motion. , 



There are four straight and two oblique muscles ; the 

 straight very large, much beyond what can be required merely 

 to uiove so small an eye: the rectus internus and externus are 

 strongest, they are five inches in circumfereiKe, while the su- 

 perior and inferior are only three and a half. 



In tiie structure of the ear, the only remarkable circum- 

 stance is the great capacity of the cavities in which the sej^i- 



