PHYSIOLOGY OF SEX AND REPRODUCTION. 



237 



liberated, the mother animal has been sacrificed in reproduction. 

 ' ' The death is an altogether inevitable consequence of the reproduc- 

 tion." 



Nor is this sacrifice confined to the incipient multicellular 

 organisms. Thus in some species of the annelid Polygordius, the 

 mature females break up and die in liberating their ova. This is 

 approached, but suggestively avoided, in a genus of capitellid sea- 

 worms (C/itomastus). The whole organism is not sacrificed, but only 

 an abdominal portion of the body. This is, in fact, one of the key- 

 notes to reproductive differentiation, — the sacrifice is lessened, and the 

 fatality thus warded off. 



But again, we find in some threadworms or nematodes (for 

 example, Ascaris dactyluris) that the young live at the expense of the 



Fig. 94.— Orthonectids, showing the rupture of the female in liberating 

 the germs. — From Goette, after Juiin. 



mother, until she is reduced to a mere husk. In fresh-water Pofysoa, 

 Kraepelin notes that the ciliated embryo leaves the maternal body- 

 cavity through a prolapsus uteri of the sacrificed mother. In the 

 precocious reproduction of some midge larvae (C/n'ronomus, &c), the 

 production of young is fatal through successive generations. 



Both Weismann and Goette, though with different interpretations, 

 note how many insects (locusts, butterflies, ephemerids, &c. ) die a few 

 hours after the production of ova. The exhaustion is fatal, and the 

 males are also involved. In fact, as we should expect from the 

 katabolic temperament, it is the males which are especially liable to 



