THE TARPON 



173 



The pupil is 17 m.m. in diameter. The margin of the iris is 

 hidden under an opaque border extending for 8 m.m. into the 

 clear cornea. When this is scraped away a most interesting 

 and unusual feature is discovered. In the lower and inner part 

 of the iris at the inner margin is a circular space about 3 m.m. 

 in diameter in which the outer layer is absent. At the lower 

 portion of this is a line passage through which a probe can- 

 not be passed nor fluid forced but which is probably a valve 

 opening from the posterior chamber. 



At the iris margin behind the iris is an attached membrane 

 constituting the outer and anterior portion of the vitreous 

 humor. Immediately above this is the pigmented band of 

 fibrous tissue to which the inner pole of the lens is attached. 



The lens is most distinctive. It is globular like that of most 

 fishes, having a diameter of 14 m.m. At each of its lateral poles 

 is an extension of lens substance to which is attached a broad, 

 smooth, fibrous membrane (the processus falciformus). This 

 projecting substance is about 4 m.m. in extent and is set in a 

 position opposite to that of the equatorial diameter to which 

 the vitreous is lightly attached. 



Sketch of the crystalline and vitreous. The projections (1 

 and 2) from the poles of the crystalline lens differ in appear- 

 ance, that on the nasal side, No. 1, is broader and its termina- 

 tion is continuous with the vitreous,- No. 3. That on the tern- 



