SECONDARY WANDERINGS. 



69 



merely to assist their wanderings are cast off, and replaced by new 



structures, which subserve their altered conditions of life. Asa general 



rule, Entozoa, in this second developmental stage, show a considerable 



likeness to the fully formed ani- 



mals, but differ in various direc- 



tions. The sexual organs, for 



instance, are incompletely de- 



veloped, or even absent, so that 



the organization is, on the whole, 



less differentiated, in accor- 



dance, certainly, with the com- 



paratively simple and uniform 



conditions of life. The embryos 



remain quiescent, and imbedded PlG . 46< _ A piece of liver from the rabbit> 



in the tissue of organs, generally showing passages made by Cysticercus pisi- 



..-, . , . , , 



within a cyst, which, as we have 



formis. 



" 



seen, is formed by growth of the connective tissue, or secretion 



FIG. 48. Aspidogaster conchicola. a. Embryo ; 

 b. Young animal, not sexually mature (after Aubert). 



FIG. 47. Archigetes Sieboldi. 



by the growing body of the parasite, and feed on the substances 

 immediately surrounding them (Fig. 45). 



