494 HEMICHORDA 



occur together, there is no compound organism in the strict 

 sense. A stalk on the ventral surface of the body of a 

 Cephalodiscus produces buds, but these are separated off from 

 the parent. Yet they remain close together within the shelter 

 of a secreted "house" which is almost more like a firm gelatin- 

 ous seaweed than the encasement of a scion of the Chordata. 



