692 C. E. McCLUNG 



and denies the presence of such an unpaired element in the female 

 cells. 



Voinov ('04) deals only with the behavior of nucleolar bodies. 



Brunelli ('09) states in this paper many of the views which he 

 elaborated later in his study of Tryxalis. Briefly, he finds the 

 21 spermatogonial chromosomes of Gryllus converted into 10 

 tetrads plus the accessory chromosome. The prophase chromo- 

 somes may be interpreted as double rings, which in the metaphase, 

 take on a variety of forms due to the point of fiber attachment 

 and to the fluidity of the chromatin. The form in the metaphase 

 may vary from that of the prophase for these reasons. In the 

 metaphase the chromosomes are arranged in 'superposition,' and 

 the half rings, representing spermatogonial chromosomes, separate. 

 Fibers attach at the center of the half rings and the anaphase 

 chromosomes are split Vs.- The first spermatocyte mitosis is 

 reductional and the second is equational. 



Payne ('13) in a short paper gives an account of the behavior 

 of the accessory chromosome in Gryllotalpa vulgaris and describes 

 an unequal tetrad, the large member of which always accompanies 

 the accessory chromosome in its unipolar movement in the first 

 spermatocyte mitosis. For our present purpose we may note 

 that the diploid number, 23, is reduced to the haploid, 12, in the 

 usual manner so as to leave an unpaired accessory chromosome. 

 Baumgartner ('11), in an abstract of a paper read before the 

 American Society of Zoologists, reports similar conditions in 

 Gryllotalpa borealis. 



d. Blattidae 



Farmer and Moore ('05), after a study of a number of plants 

 and animals, conclude that there is a typical series of processes, 

 common to all multicellular organism.s, in the reproductive cycle. 

 Among the forms studied was Periplaneta americana and the 

 processes of m.aturation in the male are thus conceived: (1) The 

 chromosomes are morphologically continuous from generation 

 to generation and the reduced number of the first spermatocyte 

 is derived from the diploid spermatogonial series by fusion of 

 homologous pairs. Details of this process are not clearly given 



