290 SEXUAL RELATIONS OF 



distinctly saw spermatozoa. In the parasitic comple- 

 mental male of S. vulgare, I also most plainly saw sper- 

 matozoa. In the parasites of S. rostratum, S. Peronii, and 

 S. vittosum, the external male organs were present. I 

 may here jnst allude to the facts given in detail under 

 Ibla, showing that it was hardly possible that I could be 

 mistaken regarding the exclusively female sex of the 

 ordinary form of I. Cumingii, seeing how immediately 

 I perceived all the male organs in the hermaphrodite 

 I. quadrivalvis ; and as the parasite contained spermatozoa 

 and no ova, the only possible way to escape from the 

 conclusion that it was the male and L Gumingii the female 

 of the same species, was to invent two hypothetical crea- 

 tures, of opposite sexes to the Ibla and its parasite, and 

 which, though Cirripedes, would have to be locomotive ! 

 I insisted upon this alternative, because if the parasite of 

 I. Cumingii be the male of that species, then unquestion- 

 ably we have in I. quadrivalvis a male, complemental to 

 an hermaphrodite, — a conclusion, as we have seen, hardly 

 to be avoided in the genus Scalpellum, even if we trust 

 exclusively to the facts therein exhibited. 



With respect to the positions of the parasitic males, in 

 relation to the impregnation of the ova in the females and 

 hermaphrodites, it may be observed that in the two male 

 Iblas, the elongated moveable body seems perfectly adapted 

 for this end ; in the males of the first three species of 

 Scalpellum, the spermatozoa, owing to the manner in 

 which the thorax is bent when protruded, would be easily 

 discharged into the sack of the female or hermaphrodite; 

 this would likewise probably happen with the comple- 

 mental male of S. rostratum, considering its position within 

 the orifice of the capitulum, between the mouth and the 

 adductor scutorum muscle. The males of S. Peronii and 

 villosum being fixed a little way beneath the orifice of the 

 sack, below the adductor muscle, are less favorably situated, 

 but the spermatozoa would probably be drawn into the 

 sack by the ordinary action of the cirri of the hermaphro- 

 dite, and therefore would at least have as good a chance of 



