40 S. ZUCKERMAN 



well. His own view was that cells from the germinal epithelium 

 divide mitotically, and either give rise to granulosa cells or 

 pass into the interior of the ovary as interstitial cells, where 

 they may later become transformed into oocytes. He de- 

 scribes how the nucleus of an interstitial cell may enlarge, with 

 the chromatin filaments of the nucleus separating over the 

 increased area in the form of a loose meshwork interspersed 

 with chromatin nodules. This he regarded as the leptotene 

 stage of meiosis. He then goes on to describe what he con- 

 sidered to be a synaptic condition of the nucleus, indicated 

 by the massing of the filaments into a lump on one side of 

 the nucleus. A pachytene stage is also pictured, in which the 

 synaptic lump is resolved into coarser and more bulky fila- 

 ments. On the other hand, Rao states that the diplotene phase 

 is either fugitive or does not occur, since the dual arrangement 

 of the filaments cannot be made out. All these interpretations 

 are based entirely upon an analysis of separate cells, and Rao 

 is careful to point out that he did not have the opportunity 

 of studying oogenesis, for purposes of comparison, in foetal 

 ovaries. 



Hamlett's (1935) observations of oogenesis in the mature 

 armadillo relate to a single pregnant specimen which had "a 

 button of tissue projecting abnormally from the otherwise 

 smooth surface" of the ovary. His histological description 

 accords closely with that of Gerard and Herlant for the lemur, 

 but Hamlett, nevertheless, regards his specimen as illustrating 

 not the normal state of affairs, but "what must happen in the 

 rare instances" when the epithelium of a mature ovary in 

 which the tunica albuginea is well developed "undergoes 

 proliferation". "The cells are forced outward, not inward, for 

 they are incapable of penetrating the dense layer of connective 

 tissue and smooth muscle forming the tunica." He goes on to 

 say that "any postnatal replenishment of oocytes" from the 

 surface is normally impossible in the armadillo, as well as in 

 other animals whose ovaries are invested by a dense tunica. 



The oogenetic phenomena described by Gerard and Herlant 

 and by Hamlett seem, at first reading, to be similar to those 



