588 THE AMERICAN NATURALIST. [VOL. XXXVIII. 



numerous plastids and not infrequently a considerable amount 

 of food material. The primitive female gametes were provided 

 with cilia like the male, but with their increase in size came a 

 sluggishness of movement which resulted in much shorter peri- 

 ods of motility on the part of these sexual cells. There are 

 some algae (Ectocarpus siliculosus, Cutleria, Aphanochaete) 

 whose motile female gametes come to rest shortly after their 

 escape from the oogonia and are fertilized as quiescent cells by 

 the active sperms. These female gametes at the time of fertili- 

 zation behave physiologically like eggs although their develop- 

 ment shows a morphology identical with the sperm. When 

 such female gametes dispense with cilia entirely they become 

 eggs. 



The absence of cilia does away with very much of the com- 

 plexity which we have just described for sperms. There is no 

 trace of the blepharoplast in the egg and no indication of the 

 activities associated with this structure, so conspicuous in sper- 

 matogenesis. The large motile female gametes of such Algae as 

 Bryopsis, Cutleria, Aphanochaete and certain species of Chlamy- 

 domonas and Ectocarpus will probably show some interesting 

 conditions when the details of their cell structure and develop- 

 ment are known, for some of these types are likely to throw light 

 on the relation which the blepharoplast bears to other structures 

 in the cell. 



The eggs of all plants (Fungi excepted) are believed to be 

 richly stocked with plastids in sharp contrast to the sperms which 

 are entirely destitute of these structures in all groups above the 

 algae. The plastids in the eggs of Algae contain the pigments 

 characteristic of the respective groups giving these cells a very 

 rich coloration and sometimes an elaborate internal structure 

 since these plastids or the single chromatbphore generally main- 

 tain a symmetrical relation to the nucleus. Leucoplasts (see 

 Fig. \\a) have been found in the eggs of angiosperms 

 (Schimper, '85) but detailed studies on the cytoplasm of such 

 cells in spermatophytes, pteridophytes and bryophytes are 

 greatly to be desired to determine the history of plastids dur- 

 ing the development of these germ cells and at later periods 

 after fertilization. 



