168 



HEREDITY AND SEX 



formation of liver and lungs and pancreas from the 

 digestive tract. The following case may perhaps 

 be considered as supporting such an hypothesis. In 

 a hermaphroditic worm, Criodrilus lacuum the ovaries 

 lie in the thirteenth and the testes in the tenth and 

 eleventh segments. If the anterior end be cut off, a 

 new one regenerates, as shown by Janda (Fig. 85), 



Pig. 1. 



Fig. 2. 



Kg.3- 



Fig. 4. 



Pig. 6. 



Fig. 85. — 1, anterior end of normal criodrilus, showing reproductive 

 system; 2-5, regenerated anterior ends. (After Janda.) 



in which the ovaries and testes reappear approximately 

 in their appropriate regions. It is true their location 

 is more hable to vary than in the normal worm, but 

 this is unimportant. 



In the Gephyrean worm, Bonellia viridis, the degen- 

 erate male is parasitic on the female. Baltzer has dis- 

 covered that every fertihzed egg is potentially a male 

 or a female. For, if the swimming larv2e have a chance 



