176 THE EVOLUTION OF CONTINUITY 



attached gonophores are usually unisexual, and the sexual 

 elements are produced in two special situations : either 

 on the walls of the radiating canals, or on those of the 

 manubrium (Fig. 50). 



If we picture a medusoid with female elements on the 

 manubrium and male elements on the canals, we cannot 

 fail to see that its plan might stand for that of a typical 



Fig. 50. — Diagram showing the site of production of sexual 

 elements in medusoid gonophores. In a, on the walls of the 

 manubrium ; in b, in those of the radiating canals near the 

 rim of the bell. 



Angiosperm flower. And when it is remembered that the 

 vegetative part of the Angiosperm shows signs of ancestral 

 zooidal repetition, and that the typical flower is terminally 

 compressed to form a species of megazooid in a similar 

 way as is the hydrozoal medusoid gonophore, we feel that 



Fig. 51. — The significance of the Angiosperm flower. 



the resemblance is no matter of chance but reflects 

 derivation. 



We would not expect the ancestral medusoid bell to be 

 represented in the plant flower, for this organ was adapted 

 for locomotion in a watery medium, and for rhythmic 

 respiration and water- vascular circulation ; but we should 

 expect that the structures which bore the sexual elements 



