5o6 LIFE : OUTLINES OF GENERAL BIOLOGY 



hermaphrodites (egg-producing and sperm-producing in one), as 

 well as on female barnacles, Darvvin suggested that in the first case 

 the advantage of their presence would be in securing cross-fertilisa- 

 tion. In a nimiber of parasitic cope pod crustaceans the relatively 

 large female has attached to her body a very minute male; and the 

 fertilisation of the eggs is in this way ensured. For the females are 

 often ensconced in parts of fishes where they are not readily acces- 

 sible. It is quite possible that the close attachment of a young male 

 to the body of the female is in itself a cau.se of the inhibition of 

 growth; but this has not been proved for crustaceans. Another 



Fig. 76. 



Angler-fish {Edriolvchnus schmidti), showing Male Parasitism. After Tate 

 Hegan. .\. the female (F) with the minute male (M) attached behind the 

 gill-covcr, which is marked by a spine (SP). B, the same enlarged, showing 

 the pigmy male (M). with testes (T), intimately attached to the female (F). 



strange case is that of small wormish creatures called Myzostomes, 

 which live fastened to the feathery arms of the beautiful sea-lilies. 

 Some are hermaphrodites and some are females; and here again 

 there are attached pigmy males. While a mother is indispensable, 

 a father may be reduced to a mere appendage, or suppressed alto- 

 gether! Many of the minute Wheel Animalcules or Rotifers have 

 males less than half the size of the females ; and these dwarfs, though 

 free living and sometimes energetic, have not even the honour of 

 fatherhood, since most of the Rotifers illustrate Parthenopeia. 

 In other words, they mainly multiply by virgin birth. 



There is no denying that the males or drones among social insects 

 tend to be parasitic, in the sense that they do not fend for them- 



