THE GENERAL SCHEME 



E55 cell 



Fio. 5. Diagram of simple many-celled animal {Hydra) cut lengthwise 

 to show the egg cell and the testis with its sperm cells. Compare with 

 the photographs of the same subject, Plate II. From Attaining Woman- 

 hood, by George W. Corner, by courtesy of Harper and Brothers. 



mals, notably the sponges and jelly fishes. In the common 

 fresh-water polyp, Hydra, for example (Fig. 5 and Plate I), 

 the buds develop from the side of the tubular parent and 

 ultimately break away. An interesting development of this 

 pattern is well seen in Obelia, a hydra-like animal often 

 studied in biology classes, in which the bud is not exactly like 

 the parent, but becomes a free-swimming medusa (jelly fish) 

 which in turn produces a generation of polyps like the original 

 hydroid. 



In some of the sponges the buds or gemmules are formed 

 internally and must await the death and decay of the parent 

 before they can get free to begin their own career. 



I have not space here to review all the modifications of 

 this general sort that occur in the more primitive part of the 

 animal kingdom. Some of them are decidedly bizarre. The 

 process of budding can, however, be considered (with certain 



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