640] 



FARA^ITJC COFEPODS 



453 



phores. 'lliese are maniimlated by tlie free maxilhr of 

 tlie male and are ultimately attached near the genital 

 pores of tlie female. I'he spermatophore.s contain a 

 cement-like material which aids in their attachment. 

 They are also lillcd with large numbers of mature sper- 

 matozoa which wander through the genital pores and 

 become stored within the spermatheca of the female. 

 Here these male gametes remain dormant until the ova 

 of the female are ri])e for fertilization. When the wander- 

 ing of all the spermatozoa has been completed the 

 spermatopliores collapse and soon come to resemble 

 transparent, shell-like, yellowish spheres. The female 

 may be fertilized more than once. Oftentimes as many 

 as six spermatophores may be found clinging to the 

 genital pores of some of the females, showing that these 

 have been fertilized three times. 



After fertilization, the male drops off the body of the 

 female and soon dies. The female, however, lives on and 

 completes the life-cycle. She now undergoes extreme 

 degeneration, increases enormously in size, and develops 



ill her alxloiiii'ii. Al the -aiiic tiiii(> two -Icndci' iriem- 

 l.ranou^ c--sao> mako tlu'ir api-;ir;ni.v at tlir i-o.torior 

 mar-in of the feiiiale-s body. When the ova aiv ripe 

 they are passed down through the oviducts and as they 

 migrate past the spermatheca they are fertilized by the 

 stored spermatozoa. The embryos are then transferred 

 to the egc'-sacs where they carry on their comjilete de- 

 velopitiont. In about a month the young are liberated as 

 free-swiiiimina' lai\;e ready to begin the cycle again. In 

 S„h,r:,n<,ln > Jfunr/^ii two batches of young are ])roduced, 

 eaelt numberiim- about one hundred and twenty individ- 

 ual>. After all the young have been lil)ei-ated. the adult 

 fenialo die and soon deteriorate on the tisane. ,,r the 

 host. 



Although these copepods are not. ordinarily, very 

 dangerous to fish in their natural Jiaunts, yet t'roni the 

 standpoint of fish-culture they are of considerable eco- 



