62 H. H. NEWMAN. 



cleavage mitoses but as more or less abnormal maturation figures, 

 that the so-called multicellular embryos are degenerative prod- 

 ucts, and that teratoma and other kindred phenomena must 

 be explained in some other way than as the products of partheno- 

 genetic cleavage of ovarian ova. This conclusion is, I believe, 

 fully justified by the evidence then available. 



Since this review and judgment of Bonnet several authors have 

 reopened the question but have failed to agree. Spuler (1900) 

 insists that the figures which he finds located in the center of 

 ovarian ovocytes, after the extrusion of one polar body, are 

 cleavage spindles, because normally ovulation occurs before this 

 stage and the ovocytes do not develop thus far unless fertilized. 

 He places especial emphasis on finding one ovum in which a 

 centrally located spindle occurred in an egg that had two polar 

 bodies. This, however, is probably a case similar to that 

 described by the present writer (Newman, '12) as due to a 

 precocious division of the first polar body, the spindle being 

 merely the second maturation spindle. Spuler fails to add any 

 material strength to the affirmative side of the question reviewed 

 by Bonnet. 



Van der Strict (1901) working with the bat ovary also took 

 the affirmative side of the question as the result of his discovery 

 that ovocytes of the second order occasionally divided mitotically 

 into two cells of approximately equal size. This division could 

 not, he thought, be considered as an anomalous polar body 

 formation, nor as a mitotic division due to degeneration, nor as 

 fragmentation, but only as the beginning of parthenogenetic 

 division. I am inclined to think that Van der Strict was dealing 

 with phenomena closely akin to those described in the present 

 paper for the armadillo, but he failed to make his evidence 

 especially convincing. 



L. Loeb (1901) takes a position similar to that assumed by 

 Spuler and Van der Strict and goes a step further in that he holds 

 that the subsequent fragmentation of the egg material into 

 nucleated and enucleated pieces is a progressive phenomenon 

 akin to the parthenogenetic development of the egg of Chcctop- 

 terns which, as Lillie has shown, develops into a larva of con- 

 siderable complexity without any nuclear cleavage. Loeb figures 



