178 Dr. R. Greeff on Autolytus prolifer. 
Syllis prolifera. Hence, therefore, the nurse would at the 
same time produce asexually by gemmation an offspring des- 
tined on its part to generate sexual products, and likewise be 
capable of giving origin to sexual products (namely, ova) in 
unaltered segments of its own body. Nevertheless this case, 
when carefully considered, scarcely presents a serious diver- 
gence from the ordinary process of prolification in Autolytus 
as it has been concordantly described by authors. In this, as 
has already been remarked, the bud-sprouts are originally 
produced, not at the end of the parent body, but nearly in its 
middle, by becoming as it were inserted by gemmation between 
two segments, and in such a manner that the youngest sprout 
is always the foremost, and consequently nearest to the anterior 
part of the primary animal. By this means, therefore, the whole 
primary individual is divided into two parts, an anterior and a 
posterior, separated by the intervening sprouts and removed to 
a greater distance apart in proportion as the number of these 
increases. But the hinder part of the primary individual is 
not lost, but becomes formed, like the buds, into a new indivi- 
dual, which is also, like these, destined to generate sexual pro- 
ducts. ‘Therefore here also we see sexual products originate 
in a previously continuous part of the primary individual, in 
primitive segments of the original nurse, only that this part is 
no longer in direct connexion with the anterior primary part 
as was the case in the example above described by me. oo 
vertheless it cannot be denied that the two cases present a 
great analogy, inasmuch as, in both, sexual products originate | 
in primitive segments of the original nurse-body. 
hrough these circumstances, as I would particularly indi- 
cate, the mode of reproduction of Awtolytus (which, as above 
described, always produces at least one offspring by fission) 
remarkably approaches that of Syllis prolifera, in which, ac- 
cording to the investigations of Krohn * and QuatrefagesT, 
the new individuals originate only by fission. It appears, 
however, on closer examination, as Ehlerst was the first to 
show, that in Syllis prolifera also the increase by fission is 
only apparently general, but is fundamentally for the most 
art produced by gemmation as much as in Awtolytus. Thus 
it is certain that the segments of the parent animal are made 
use of for the formation of new individuals; that is to say, 
those which are by this means thrown off are ina oidiadlleg 
replaced by gemmation from the primary individual at the 
point of separation, and this either while the young’ are still 
* Wiegmann’s Archiv, 1852, p. 66. t Loe. cit. supra. 
t Die Borstenwiirmer, p. 208. 
