THE NATURAL 



plication takes place only in space. In time the product 

 is a contraction, two giving one. 



Scissiparity is compatible with the existence of separate 

 sexes, as in the starfish. This fantastic animal with no 

 instrument save its suckers opens oysters, envelops them 

 with its stomach which it unbellies (vomits), devours 

 them. It is not less curious in reason of its variety of 

 reproductive mode, serving itself of sexual apparatus, or 

 budding, or casting an arm which becomes a new creature. 

 Thus it is difficult to class animals according to their 

 manner of reproduction; hermaphrodism is another 

 block. This mode is doubtless primitive, since it is of 

 the type of protozoaire coupling, but it is greatly com- 

 plicated when it persists, for example up to the moment 

 where it disappears in the mollusk series, whereof some 

 possess so luxurious a love-organism. The simple and 

 very naive form, that in which the sperm and the eggs 

 are produced simultaneously inside the same individual, 

 is found only in inferior organisms. Normal partheno- 

 genesis belong equally to summary and to complicated 

 animals, to wheel-animals and to bees. Among arthro- 

 pod es, that is to say among insects in general, the sexes 

 are always separate, save in certain tardigrade arachnids, 

 but these are the ones which offer the finest cases of 

 parthenogenesis, generation without aid of the male. 

 The term need not be taken literally. For as there is no 

 indefinite scissiparity without coupling, there is no un- 

 limited parthenogenesis without fecundation: the female 

 is fecundated for several generations which transmit this 

 power, but there comes a day when the female who has 

 not encountered a male gives birth to males and females. 

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