WILCOX: SPERMATOGENESIS. 15 
and were thus unprejudiced in favor of rings or Vierergruppen in mak- 
ing their drawings. The older works will be mentioned first, and the 
important works of Boveri ('90), Brauer (93, ’94), Häcker (93), Hen- 
king (90, ’91, *92), and vom Rath (’91°, ’92, 93), will be considered 
later. 
Flemming (’87, pp. 444, 445) saw Vierergruppen in the Salamander. 
Figures 46-50 of his paper show chromosomes arranged in groups of 
four, the groups being scattered quite irregularly over the spindle, 
much as vom Rath figures them in his latest paper (93). Flem- 
ming considered this arrangement as abnormal: “Sie [the group- 
ing into fours] kann wohl in der That als eine Anomalie bezeichnet 
werden, obwohl ich noch nichts darüber weiss ob aus den Folgestadien 
etwas normales werden kann oder nicht, . . . es finden sich also Grup- 
pen von je vier Kügelchen von denen je zwei aneinanderhängen. Diese 
liegen anscheinend ganz regellos über die ganze Spindel hingestreut, 
nur offenbar mit der Tendenz sich nach den Polen anzuhäufen.” Vom 
Rath calls attention to Flemming’s explanation of these figures, and 
holds, quite rightly, that the groups are moving, not as Flemming 
imagined, toward the poles, but toward the equator, there to be separated 
into bivalent dumb-bells. Flemming believes he finds a tendency to 
irregularity in those spindles which bear four-grouped chromosomes, and 
considers such irregular spindles as so many stages in the degeneration 
of a bipolar spindle into a tripolar one. If with Flemming it is denied 
that the groups of four oocur in the regular course of development, it 
must be concluded that these are degeneration stages. 
Platner (’86) has figured in Helix pomatia several stages of rings and 
their division without so interpreting them. Figure 4 of his article 
“Ueber die Entstehung des Nebenkerns,” eto., shows very clearly the 
ring condition previous to division, In his Figure 5 are groups of four 
chromosomes. Figure 12 shows rings on the equator of a spindle, and 
Figures 15-17 are metakinetic and dyaster stages, in which the spherical 
chromosomes are coupled into dumb-bell figures and some of the dumb- 
bells have rotated 90° and are ready for the second division, just as I 
have seen them in Caloptenus. 
I would call attention also to the following cases drawn from the 
literature of the subject: La Valette St. George (85, Figs. 16, 17, '86, 
Figs. 11, 21, 22), Zacharias ('87, Taf. VIII. and IX.), Kultschitzky ('88, 
Fig. 3, and '88*, Figs. 16, 17, 22), Carnoy (85, '86, and 86%), Guignard 
(91), Baranetzky (90, Figs. 23, 26, 40), Hermann ('89, Fig. 31), 
Lukzanow ('89, Figs. 21, 23), Henking ('92, Figs. 101, 153, 190, 216, 
