THE BLINDFISH 



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on the slime by a series of leaps. After birth the young are carried about by the 

 female in a thin-skinned sac divided by a partition, until they are sufficiently ad- 

 vanced to take care of themselves. When swimming, these fishes frequently go on 

 the surface with the eye half in and half out of the water; and it is in accordance 

 with this habit that the eyes are divided, the upper portion being able to see in the 

 air, while the lower is adapted for vision under water. That such is really the 



FEMALE AND MAI.E DOUBLE EYE. 



(One-third natural size.) 



case, is proved by the structure of the lens of the eye. In terrestrial animals the 

 lens is lenticular, that is to say of the shape of .two watch glasses put edge to edge; 

 whereas in ordinary fishes, which have to see in such a dense medium as water, the 

 lens is spherical. Now in the double eye that portion of the organ of vision which 

 is above the level of the water has the lens lenticular, while in that portion which is 

 below the water the lens is spherical. In Brazil the flesh of these fish forms an 

 article of consumption. 



THE BLINDFISH Family A MBLTOPSID^ 



The celebrated blindfish (Amblyopsis spelcea] from the Mammoth Cave in 

 Kentucky, the Wyandotte Cave in Indiana, and the subterranean streams which 

 appear to connect the waters of the two, is generally regarded as the typical repre- 

 sentative of a family closely allied to the last. This fish, which does not exceed 

 five inches in length, and breeds viviparously, closely resembles the genus Cyprin- 

 odon in that certain specimens (which have unnecessarily been separated as 



