506 CHARLES W. HARGITT 
Among the anomalous aspects of cleavage which I have en- 
countered in the development of these and other hydroid eggs 
not the least singular or significant is the occurrence, now and 
then, of what may be designated as blastomeric autotomy. That 
is to say, occasionally one finds during the earlier stages of cleav- 
age, most commonly at the first, the complete separation of the 
primary blastomeres, which continue to develop as independent 
eggs, and from which independent embryos arise, giving origin 
to two polyps. I have called attention to something of this in 
Pennaria. The same thing has been found in at least two cases 
in Hydractinia. In one case actually followed from beginning to 
end the sequence of events may be briefly described. At the first 
cleavage of an egg which was in a marked degree unequal, the 
two blastomeres separated entirely, each part developing quite 
apart, and in a perfectly independent fashion. One of these seg- 
mented in a fairly regular and symmetrical fashion, while the other 
portion was markedly irregular from the first. It should be ob- 
served that the rate of cleavage in the former was much slower 
than in the latter, which exhibited a marked tendency toward 
amoeboid aspects as shown in the figures already cited. 
It seems perfectly clear, therefore, that we have in these aspects 
of development a perfectly normal, and not particularly rare 
mode of segmentation, involving the origin of two, and probably 
even three or more embryos from a single egg, in a perfectly 
natural and spontaneous way. 
Among these anomalous aspects, which were numerous as well 
as various, those shown in text figs. 4, B and C will be interesting. 
In this case the first cleavage was about normal, beginning at the 
animal pole and extending downward to the lower, where the 
blastomeres remained attached by the connective shown in fig. 
A for some time. The second cleavage was the not unusual type 
shown in fig. B where it was directed centrifugally and in a hori- 
zontal instead of a vertical plane; and as it continued the connec- 
tive was resorbed, leaving the two blastomeres quite free for a time 
during which they moved into the position shown in the figure, 
when the vegetal blastomere of the one side came into contact 
with the animal blastomere of the opposite part, in which posi- 
