Il6 H. H. NEWMAN. 



Fig. 1 8 as it appears in paraffin sections. The two zones are 

 very sharply defined. The first maturation spindle, which one 

 would expect to find in the thick middle part of the formative 

 zone, occupies a position near the equator of the cell in the 

 thinned-out peripheral portion of the formative zone that over- 

 laps and partly surrounds the deutoplasmic mass. What is the 

 significance of this peculiar position of the polar spindle? Ex- 

 actly the same conditions are met with in the egg of Dasynrus 

 and in that animal are interpreted by Hill as indications that the 

 ovocyte has undergone a complete reversal of polarity. Accord- 

 ing to him the formative protoplasm occupies now the vegetative 

 pole, while the deutoplasmic mass lies at the animal pole. This 

 interpretation is borne out by the peculiar position of the spindle 

 which occupies a position as near the animal pole as is possible 

 without leaving the formative protoplasm or the peripheral 

 position necessary for the extrusion of the polar body. 



In view of these conditions we may well hesitate to apply any 

 sort of phylogenetic interpretation to the " telolecithal " char- 

 acter of this ovum. Doubtless we have here a polarity of the 

 germ cell which is merely incidental to changes connected with 

 the extrusion of the deutoplasm, which I believe occurs in the 

 armadillo in much the same fashion as that described by Hill for 

 Dasyurus. The evidence for this conclusion forms the material 

 for a subsequent paper. The armadillo ovum is to be considered 

 as primitive not because it shows a "telolecithal" organization 

 but because it is so nearly identical in many details with that of 

 a number of marsupials. 



With the rupture of the germinal vesicle and the establishment 

 of the first cleavage spindle a very marked diminution in the 

 size of the nuclear material is manifest. This is due to the loss 

 of much fluid and perhaps some chromatin to the cytoplasm, 

 and also to a marked condensation of the remainder, as will be 

 shown more in detail when the nuclear phenomena come up for 

 discussion. 



