Germ Cells of Leptinotarsa Signaticollis. 185 



The other alternative, namely, that the odd body divides longi- 

 tudinally in the second division is more in accord with well 

 established observations in other forms, and furthermore meets 

 with no objections in the appearance of the various division 

 stages. If we accept this interpretation, the case is exactly similar 

 to Syromastes except that the order of division is reversed, the 

 bi-partite dividing in the second division instead of the first, thus 

 giving two classes of spermatozoa, one with sixteen and one with 

 eighteen chromosomes. An identical instance would be seen in 

 Phylloxera (Morgan '09), where the odd body is equivalent to 

 two chromosomes which divide only in the second division, and 

 then longitudinally. 



On this basis the somatic tissues of the female would contain 

 two more chromosomes than those of the male, and the fertili- 

 zation formula for signaticollis would be: 



Egg 18 + sperm 16 = oosperm 34 (c?). 

 Egg 18 + sperm 18 = oosperm 36 (9). 



However, the tangled condition of the chromosomes in dividing 

 somatic cells, prevented verification of these points by direct 

 observations. 



My observations of the maturation spindles of the egg are very 

 incomplete, and I am unable to say whether or not there is an un- 

 equal distribution of chromosomes such as occurs in the first 

 spermatocytic division. It is possible that while the bi-partite 

 nucleolus appears in the ovocyte, at the same time as in the sper- 

 matocyte, its subsequent behavior in the maturation divisions 

 is entirely different. 



Is the nucleolus of the ovocyte the homologue of the nucleolus 

 of the spermatocyte? The transformations accompanying the 

 long growth period of the ovocyte make it a very difficult matter 

 to follow the history of this body through to the maturation 

 spindles. The last stage at which it can be satisfactorily made out 

 is shown in Fig. 43, which represents a section of the nucleus of an 

 ovocyte. From this there occurs a gradual transition to the con- 

 dition seen in Fig. 44, where in place of one, five rounded basic 



