174 THE TARPON 



poral side, No. 2, is also continuous with the vitreous. Both 

 sides are also attached by hroad pigmented fibrous bands 

 which are firmly attached on the one end to the lens projection 

 and on the other to the juncture of the iris margin and choroid 

 allowing a certain amount of rotation and lateral motion to 

 the lens but still holding it in its position behind the pupil 



These lenticular enlargements which are firmly attached to 

 the juncture of the iris and choroid, differ in form. That on 

 the nasal side being fan-shaped and continuous with the 

 vitreous of which it forms a part; and that on the temporal 

 side has an opening in its center into which is attached the 

 pigmented band. It is also on its under side continuous with 

 the vitreous. The lens is swung in a hammock-like membrane 

 of smooth fibres which envelopes its posterior half by which 

 it is moved. 



The vitreous is also somewhat loosely attached to it along 

 its whole equatorial extent between the poles. The vitreous is 

 also attached firmly around the optic nerve entrance. Within 

 the vitreous are rounded portions of greater density which 

 may change their position by pressure behind the crystalline 

 lens so as to give added focal values in different directions. 

 This movement of the vitreous is provided for by the cup-like 

 addition to the globe in which there must be a less dense fluid 

 which flows from side to side as the motion of the vitreous 

 and the lens takes place. The attachments to these projec- 

 tions on the lens are such that its motion is also accompanied 

 by a rotation of the lens. The extension of the vitreous from 

 the inner lens projection reaches to the posterior portion of 

 the valve-like opening in the iris, and is probably tubular al- 

 lowing for the equalization of pressure by the passage of the 

 less dense fluid probably of the nature of the aqueous, from 

 the posterior to the anterior chamber. 



This peculiar connection between the iris and the posterior 

 chamber is also found in the swordfish, in the octopus and 

 possibly in other of the deep sea fishes. 



