162 PRIMITIVE FORMS OF LIFE 



clearly affected either by a nutritive incapacity or by the 

 orientation of their organism towards a useless expenditure 

 of energy which destroys their alimentary reserves ; so that 

 they are, in short, impoverished organisms whose poverty affects 

 the reproductive elements themselves and imposes special 

 characters upon them. A predominance of males in an animal 

 population would therefore be a sign either of dearth or of 

 superactivity. 



This last remark leads us to consider whether the explanation 

 of hermaphroditism is not to be sought in the conditions which 

 render alimentation precarious. Among these conditions one 

 is especially evident, namely the abandonment of a free life 

 for the sedentary one, and notably for attachment to the 

 ground, which places the animal at the mercy of all the 

 variations in its environment, from which freedom in move- 

 ment would permit it to withdraw. Outside the "Phytozoa", 

 in which fixation is primitive, this attachment to the ground 

 occurs as an accidental condition in the Cirripedes, which are 

 Crustaceans, and the Tunicates which are related to Amphioxus, 

 the most primitive of Vertebrates. In both cases it leads to a 

 complete change in the conditions of existence after the animal 

 has attained the form which should normally have been 

 permanent, and results in a complete deformation of the 

 body. The Cirripedes and the Tunicates are protandrous 

 hermaphrodites, that is to say, each individual commences 

 life as a male, becomes transitionally both female and male, 

 and finally passes definitely into the female condition. What 

 does this very general phenomenon signify ? The Cirripedes 

 give us the answer to the question. Most genera of Cirripedes 

 have no males at all. Where they exist they are not fixed, 

 remain very small, and have but a short life. As the other 

 individuals, in their quality of protandrous hermaphrodites, 

 are capable of reciprocally fertilizing each other, if not them- 

 selves, the exclusively male individuals are of no use at all. 

 They are not even what we sometimes call complementary or 

 supplementary males, but simply useless males, or, if we desire 

 to give them some designation, supernumerary males. Their 

 existence merely serves to qualify the other individuals ; it 

 demonstrates that among the Cirripedes, before fixation, the 

 sexes were distinct as among other Crustaceans ; that fixation, 

 with all its hazards, has been fatal for the males, which have 



