12 
SPERMATOGENESIS OE NORMAL 
the others in size. It is a filament two or three times as long 
as the other chromosomes and it never has the ring or split 
appearance. Before the final movement of the chromosomes 
to the periphery of the nucleus, this long filament is thrown out 
into the cytoplasm (Fig. 4, ec.). In all cases examined it was 
cast out into the sphere substance which contained the centro- 
some and lay close to one side of the nucleus. 
The body thus ejected breaks up apparently, and becomes 
scattered throughout the cytoplasm. The significance of this 
phenomenon could not be determined. Whether the mass is 
simply a useless accumulation of chromatin, or whether it is 
of more vital importance to the phenomenon of maturation 
seems beyond explanation at present. There is apparently no 
diminution in the number of chromosomes, yet from its reac¬ 
tions to stains the ejected filament seems to be purely chromatic 
in nature. The chromosomes are so massed in the spermato¬ 
gonia, however, that a mistake in the count might easily be 
made. There were indications that in some cases the staining 
of the filament in question was a trifle deeper than that of the 
other chromatic elements, but the difference was ordinarily 
scarcely perceptible. Fig. 4 shows one of three adjacent cells 
in all of which the process was in progress. 
It is questionable if the extruded body can be homologized 
with the “accessory chromosome’^ of McClung^, a curious 
nuclear element which he describes as occurring in Xipliidium 
fasciatum, one of the Locustidae, and which he thinks is perhaps 
identical with the chromatin nucleolus described by Wilcox^ in 
the testicular cells of Caloptemus femur ruhrum, or in Pyrrochoris 
as recorded by Henking^. Again in Montgomery’s^ account of 
Pentatoma, McClung finds a possible parallel in a body which 
resembles a nucleolus while the cell is at rest but simulates a 
chromosome during the period of division. There is no evi¬ 
dence in the case of the pigeon to show that the ejected fila- 
1. McCIung, E. C. A Peculiar Nuclear Element in the Male Reproductive 
Cells of Insect: Zool. Bull, II, 4, 1899. 
2. Wilcox, B. V. Spermatogenesis of Calloptemus femur rubrum and Cicada 
tibicen: Bull of the Mus. of Comp. Zool., Harvard College XXVII, 1. 
3. Henking, H. Erste Entwickelungsvorgange in den Eiern der Insecten. 
Zeitsehr. f. Wiss. Zool. LI. 1891. 
4. Montgomery, Th. H. The Spermatogenesis of Pentatoma: Zool. Jahr. 
XII, 1898. 
