PARASITA. 



241 



spermatophores, has attained full development. This free -swimming copulatory 



Cyclops stage is the last stage of the male, the fertilised female, however, 



seeks a new host (one of the Gadidae), in which she undergoes marked trans- 



formation of the body 



(Fig, 114 C and D). 



The genital segment, 



which has enlarged 



for the development 



of the eggs, is now a 



large doubly-curved 



portion of the body, 



the small abdomen, 



with its truncated 



ftircal appendages, 



forming its termina- 



tion. The cephalo- 



thorax is changed by 



the addition of three 



horns which function 



as barbed hooks, 



carrying at their 



points fork-like out- 



growths. During 



these transforma- 



tions, the limbs are all 



retained, but are to a 



certain extent trans- 



formed by strong 



chitinisation. 



The remarkable 

 form Sphaeronella 



Lcuclcartii, which is n 



parasitic in the brood- ^ 



cavity of Ampliithoe, 

 is connected with 

 Lernaea by its 

 metamorphosis. 

 SALENSKY (No. 80) 

 found in SpJiaeronella 

 an extremely degene- 

 rate pupal stage fol- 

 lowing the first free- 

 swimming Cyclops 

 stage. Neither seg- 

 mentation nor limbs 

 were recognisable in 

 the sac-like body 

 which was attached 



by a larval adhering apparatus to the epimeral plates of the host. 

 led, through gradual transitionary stages, to the adult form. 



The metamorphosis of the Lernaeopodidae is best known through the works 



FIG. 114. Sexually mature stage of Lernaea branchialis (after 

 GLAUS). A, male. B, female at the copulatory stage. C and 

 D, later condition of the female transformed by parasitism, 

 slightly magnified, a', first, a", second antenna ; ff-fjy, first 

 four pairs of thoracic limbs ; g, opening of the receptaculum 

 seminis ; mxf, maxillipede ; oc, eye ; sp, spermatophoral sac ; t, 

 left testis. 



This stage 



