16 MARGARET MORRIS 



differentiated entirely without cytoplasmic cleavage, such as is 

 shown in text-figure 2, 4, or one like text-figure 2, 5, in which 

 one cell has developed to a ciliated swimming structure while 

 the other remains an inert mass. This phenomenon of differ- 

 entiation without cleavage is known in the parthenogenetic de- 

 velopment of other forms. In the egg of Chsetopterus, for 

 instance, Lillie ('02) has found it to be of common occurrence, 

 and Scott ('06) has also produced it in the eggs of Amphitrite. 



^0- 



. i;^mi::i.^r tmrn-m n::^^^^::v-..-.-;- •.- i^^r 



In both of these cases it appears to be independent of matura- 

 tion. Eggs without polar bodies may develop in this way as 

 well as those which have matured fully. In Cumingia there is 

 no evidence that the phenomenon is confined to eggs with polar 

 bodies. The preserved material does not give a complete series 

 of stages, so that the cytology of this kind of development could 

 not be worked out at this time. 



Table 4 gives the details of the experiments in which eggs 

 without polar bodies were separated from those which had un- 

 dergone maturation. The numbers are not very large, to be 



