204 BULLETIN : MUSEUM OF COMrARATIVE ZOOLOGY. 



which had formed only one polar cell, the cleavage cells contained 84 

 double chromosomes. 



As the eggs of the second type were rare and sometimes showed multi- 

 polar spindles, Brauer is uncertain whether they were really capable of 

 normal development or not. Petrunkewitsch is certain that they must 

 have been purely pathological, for he never observed evidence of any 

 such second method of maturation in his own preparations, though this 

 was the especial object of his search, and he worlicd with material from 

 the same locality, Triest, that had furnished Brauer's material, and in 

 addition with material from a second locality, Odessa, where male Arte- 

 mias not infrequently occur. 



But a moment's reflection will show that the apparently discordant 

 results of Brauer and Petrunkewitsch are readilv reconcilable. Brauer's 

 second type of maturation may have been observed in the rare male (or 

 fecundable) eggs. 



But why, then, it may be asked, did not Petrunkewitsch encounter 

 this second type of g^^, the especial object of his search, for he exam- 

 ined material from Odessa, where males frequently occur. Probably be- 

 cai;se he, as he explicitly states, worked exclusively xoith winter eggs 

 ("Dauereier"), whereas Brauer worked both with summer eggs ("Subi- 

 taneier ") and with winter eggs. Though Brauer makes no statement 

 concerning the matter, I confidently hazai'd the conjecture that the 

 second type of maturation was observed by him only among the summer 

 eggs, for in no species, so far as I know, in which parthenogenesis 

 occurs, has the development of a male animal from a winter egg ever 

 been observed. In parthenogenetic Crustacea, llotifera, and Platodes 

 alike, there invariably hatches from the winter egg a parthenogenetic 

 female. Should Petrunkewitsch study the parthenogenetic summer eggs, 

 instead of the winter eggs, produced by Artemias of the Odessa race, I 

 venture to predict tliat his search for the second type of maturation 

 will be abundantly rewarded, at least to this extent, that he will 

 find the occurrence of two maturation divisions in the male summer 

 eggs. 



It is doubtful whether the other process Qbserved by Brauer, a fusion 

 of the nucleus of the second polar cell with the egg nucleus, takes place 

 in the development of the male Artemia. More probably the result of 

 this process would be the same as that of fertilization, or of an entire 

 suppression of the second maturation division ; namely, the production 

 of a female in which the male character is recessive. This view is 

 quite in harmony with Brauer's own interpretation of his observations. 



