STUDIES ON ASPLANCHNIA EBBESBORNII. 



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rotifers present in the different cultures. At the close of the 

 active period of any one cycle, nearly all of the male-producing 

 females, within a few hours show the presence of resting eggs 

 within the uterus. These conditions are made possible by the 

 independent entrance of the sperm. 



In general the characteristics applying to the male rotifers 



lll.C. 



b.W. 



itis. 



7 



FIG. 7. Reproductive organs of a male-producing female, which contains 

 both male embryos and resting eggs; r.eg., formation of resting egg; m.e.l., male 

 embryo which shows a case of extreme degeneration, with a very delicate body 

 wall. The central mass represents a few somatic cells that still persist. No 

 bounding membrane of sperm sac was formed, and the sperm as development 

 progressed were left free in the body cavity. Later the somatic cells are all utilized 

 and the body wall becomes the bounding membrane of the large sperm sac; m.e.2 

 shows a completely developed mal,e embryo at time of birth, with testis containing 

 mature sperm; r.eg., resting egg with two distinct protective shell membranes. 



as a group are the following: diminutive size, the total absence 

 of the mouth, of the pharynx, of the jaws, of the oesophagus, of 

 the gastric glands and of the stomach and the intestine. The 



