THORACICA 381 



of hermaphrodites as Lepas is. In most, however, some individuals 

 are without female organs. These individuals are always smaller than 

 those which possess ovaries, and live within, or at the opening of, the 

 mantle cavity of the latter. In some species they almost perfectly 



scu. ^'tgm. 



--cna. 



Fig. 257. Cirripedia Thoracica. A, Lepas anatifera. B, Balamus. C, Scal- 

 pellum vulgare. D, Male of the same, enlarged. A— C, after Darwin; D, after 

 G. Smith, cna. carina ; cnl. carinolateral ; e. vestige of eye ; la. lateral ; op. open- 

 ing of mantle cavity; rst. rostrum; rstl. rostrolateral ; scu. scutum; stk. pe- 

 duncle ; t. testis ; tgm. tergum ; S, dwarf males. 



resemble these in organization, but usually they are more or less de- 

 generate, being sometimes even without an alimentary canal. As a 

 rule the more degenerate live within the mantle cavity of the partner, 

 the less degenerate on its mantle edge. In certain species, which have 



