Fish Life. 39 



instance, there are creatures that show no indiffer- 

 ence to each other. The slim, swift fishes cutting 

 the water so gracefully with their boat-shaped forms 

 tell another story of life and love. 



As far as the origin and structure of their repro- 

 ductive material is concerned, there is no essential 

 difference between them and the ascidians ; that 

 is, eggs and sperm-cells are budded off from a cer- 

 tain part of the interior of each individual. Both 

 eggs and sperm-cells are not found in the same 

 fish, however. We have here, as in all the higher 

 life, male and female. 



In the female are found the egg-cells, which are 

 produced by a certain tissue forming a double sac, 

 shaped something like an old-fashioned silk-purse. 

 Each lobe of this sac is called an ovary, and the 

 two ovaries are a definite and permanent part of 

 the creature's body. They produce the eggs, or 

 ova, and these when ripe break away from the 

 ovary, and finally pass out of the body of the 

 parent into the water. 



The eggs keep forming in the ovaries, however, 

 so when one set is ripe, another is growing. Most 

 people are familiar with fish eggs under the name 

 of roe. Those of the shad are considered a deli- 

 cacy, and in the South the roe of the mullet is 

 dried and kept for future use. The eggs of these 

 fish, as is well known, are about the size of a small 

 pin-head. In smaller fish they are often a good deal 

 smaller, but seldom, like the sperm-cells, so small 

 as to be invisible. 



