W. C. Minor upon Fission in some Annelids. 39 
My observations upon Enchytreus triventralopectinatus are sim- 
ilarly scanty, but are just sufficient to confirm and extend the 
acts observed in the two other short-lipped Naids. In all the 
cases observed, the separation was of a part wholly new formed, 
without inclusion of the older segments of the parental body. 
It is evident from the above facts, that in Stylartu longiseta, as 
Miiller and Schultze have shown is the case in S- proboscidea, the 
point of fission moves regularly forward, ring by ring, and more 
commonly in the former Naid from the 16th to the 12th pairs of 
hook combs; though the extremes between which I have known 
it to occur are the 17th and 10th. T'o judge from Miiller’s ac- 
count it occurs further back in the latter Naid. Further, that 
in Nais rivulosa, and, as far as I know, in Dero limosa, and in En- 
chytreus triventralopectinatus, all of which have short upper lips, 
the buds are given off at one point, though that point may vary 
in different Naids of the same species, or in one and the same 
aid at different times. In the latter case the variation occurs 
a part of a peculiar form of fission of which I shall speak again. 
Both “parting” (theilung), and ‘‘ budding” (knospenbildung), 
Cccur then in the Naids, and it may be added that the former 
appears to be peculiar to the genus Stylaria or to the proboscis 
ing forms, 
may here remark that the distinction made by Schultze and 
others between « theilung” an 
Venient, does not seem to me a fundamental one. The mere in- 
clusion of a portion of parental tissue in the bud does not of 
itself make an essential distinction between this and a wholl 
hew-formed, but otherwise similar, bud; nor have I been able 
; | 
see any histological or functional differences. The very fact 
that indivi 
a 
wed by the so-called “ budding,” and in another genus, Stylaria, 
e. the so-called “parting,” leads to this view. Nor, as I think, 
ough observations are largely wanting in that direction, have 
eae Processes. They are two varieties of one process; and it 
various species of aids, ert known, follow distinctly the 
one or the other plan, or tend to merge them yet more com- 
etely as one. ¢ 
bud. little detail will show how closely identical the two forms of 
ton mation are. In “parting”—‘ theilung”—as has already, 
4 great extent, been described by Schultze, we find that from 
be aes Se is seckas or Maden oy ae 
gies (ay 31) an ect kapra “parting” fo nterraptn series of bd 
ae in Nais rivulosa (Sept. 25), which leads me to expect that in some Naids 
may be redielarty present. 
. 
