B. fl.] THE HISTORY OF ANIMALS. 155 



and some maritime persona say that they obtain their purple 

 from this plant. 



CHAPTER XIII. 



1. THE pond and river fish begin to reproduce usually when 

 five months old. They all produce their ova at the begin 

 ning of summer. Like the marine fish, the females of these 

 kinds never emit all their ova, nor the males all their 

 semen, at once ; but both sexes are always found to con 

 tain a portion of the reproductive substance ; they pro 

 duce their ova at the proper season. The cyprinus five or 

 six times a-year, and especially under the influence of the 

 stars. The chalcis reproduces three times, all the rest but 

 once a-year. 



2. They deposit their ova in the stagnant parts of rivers 

 and ponds among the reeds, as the phoxinus and perca. The 

 glauis aud the perca produce their ova in strings, like the 

 frog. That which the perca produces is so involved that, on 

 account of its breadth, the fishermen collect it together from 

 among the reeds in ponds. The larger individuals of the 

 glauis produce their ova in deep water, some where it is a 

 fathom deep ; but the smaller ones in shallow water, and 

 especially at the root of the willow or some other tree, and 

 among the reeds and mosses. 



3. The fish fold themselves together, sometimes a large 

 one with a small one, and approximate the passages, which 

 some call their navel, from which they eject their respective 

 seminal matter, the females their ova, and the males their 

 spermatic fluid. Those ova with which the semen of the 

 male has been mixed immediately or in the course of a day 

 become whiter aud larger, and in a short time the eyes of 

 the fish make their appearance ; for in all fish, as in other 

 animals, this part is most conspicuous, and appears the largest. 

 But, if the seminal fluid does not touch any of the ova, as in 

 the case of sea-fish, these become useless and barren. 



4. From the fertile ova, as the fish increase in size, some 

 thing like a shell is separated ; this is the membrane which 

 envelopes the ovum and the embryo fish. As soon as the 

 seminal fluid is mixed with the ova a glutinous matter is 

 formed, which fastens them to the roots or other substance 

 on which they are deposited. The male watches over the 

 place where the greatest number of ova are deposited, auii 



