THE OVUM OF THE NINE-HANDED ARMADILLO. IO7 



second maturation division, after the first polar body has been 

 extruded. Stages up to this period are fairly numerous in the 

 present material, but there are only two examples of ovarian ova 

 completing the second maturation. Without further preliminar- 

 ies then it will be understood that all stages of the process as 

 here described are normal with the exception of those described 

 and shown in Figs. 42 and 43. 



It seems best to describe fiist the stages of follicular growth, 

 for it is very convenient to refer various stages of the developing 

 ovocyte to certain figured stages of follicular differentiation. 

 The growth period of the ovocyte, from the condition when it is 

 without a follicle to the period of maturity, is next taken up, and 

 incidentally the process of vitellogenesis and its consequences 

 receives attention. For the sake of completeness and as a 

 transition to the next study the matter of nuclear grow r th as 

 compared with cell growth is considered. Finally the nuclear 

 changes, principally those concerned with the formation of the 

 chromosomes and the acromatic structures of the maturation 

 spindles, are described in detail since chief interest appears to 

 center upon these changes rather than upon any transforma- 

 tions or reorganization of the cytoplasm. 



V. DEVELOPMENT OF THE GRAAFIAN FOLLICLE. 



There appears to be nothing especially specific in the process 

 of folliculogenesis as it occurs in the armadillo. Comparisons 

 have been made stage for stage with that of the cat, the ovaries 

 of which are of about the same size as those of the armadillo, 

 and only very minor differences have been noted. This fact, 

 in itself a matter of no particular moment, gains importance 

 when it is remembered that Rosner ('01) attempted to explain 

 away polyembryony on the basis of a very peculiar sort of fusion 

 of adjacent follicles. The following account will serve finally 

 to set at rest any misconceptions that may have been engendered 

 by Rosner 's unfortunate account. In addition we shall be 

 afforded a sort of convenient time schedule upon which to hang 

 the descriptions of the other processes with which the present 

 study is concerned; for we shall be able to refer any particular 

 phase of ovocytic or nuclear development to some definite stage 



