OP FISHES. 53 



the optic nerve ; but the organ begins at once to 

 accommodate itself, in some degree, to the exi- 

 gency of the case : the pupil diminishes its diame- 

 ter a trifle, but the fish then sees precisely, as we 

 see under water ; in reality, it is near-sighted. 

 Having no aqueous humor, the refraction produces 

 the utmost confusion for the moment. We have no- 

 ticed, that in putting a fish back into the water, after 

 having been in the air a few seconds, the vision is 

 very considerably deranged ; it swims against what- 

 ever may be in the line of its direction : indeed, 

 there does not appear to be any determinate pur- 

 pose ; but as soon as the visual organs have re-ac- 

 commodated themselves again to the water, and 

 the optic axes are restored from the distortion 

 which they received in the atmosphere, the fortu- 

 nate refugee appears again as it did before the 

 capture. 



Before leaving this subject, we cannot refrain 

 from making some observations on the structure of 

 the eyes of the Anableps Tetrophthalmus, a scaly 

 fish, from four to ten inches in length, found at 

 Surinam, and, we believe, no where else. By 

 the politeness of Captain James Crosby, of Bos- 

 ton, and the American Consul, at Surinam, we 

 have been provided with several specimens, in a 

 fine state of preservation. As it respects the hab- 

 its of the anableps, we are not informed, but the 



