176 Dr. R. Greeff on Autolytus prolifer. 
place, the definitely marked generic character; secondly, the 
relation of the bud or shoot to its primary individual, together 
with the connexion of Sacconereis and Polybostrichus with 
Autolytus; and, thirdly, some remarks upon the species hi- 
therto chiefly investigated, but still very unstable as regards 
its accurate determination, namely Autolytus prolifer, Grube. 
As regards the first pomt, I would, from my observations, 
sum up the generic character as follows (see Pl. VIII. fig.1):— 
Cephalic lobes not separated, but only indicated by an 
emargination on the lower surface. Three inarticulate frontal 
tentacles, which, by their lively movements and contractions, 
present throughout their whole length irregular transverse and 
annular furrows, so that they appear as if twisted. First body- 
segment without setigerous feet—but with two tentacular cirri 
on each side, of the same nature as the cephalic tentacles. On 
the following segments, on each side, one dorsal cirrus and a 
uniramous setigerous foot. The composite sete of the foot (fig.3) 
have on their short sickle-shaped appendage three uncini—a 
middle and two lateral ones. each cirri are wanting on all 
the segments. . 
The protrusible, finely chitinized cesophageal tube (fig. 1a) is 
surrounded by a muscular sheath, and armed at its anterior ori- 
fice with a circlet of small pointed teeth, whilst a large median 
boring-tooth, otherwise so frequently occurring as the armature 
of the mouth in the Syllidea, is wanting. The cesophageal 
tube is remarkable for its considerable length, so that only 
about the anterior half of it follows a straight course, whilst 
the second half is always folded together in loops. The ceso- 
phageal tube is followed by the pharynx or glandular stomach 
(fig. 1b) common to all Syllidea. This passes, without an 
special appendages on its lower part, into the intestinal canal, 
which runs straight backwards, and is lined in its terminal 
portion with ciliary epithelium. 
In some representatives of Autolytus an alternation of ge- 
nerations has been observed, of such a nature that from the 
primary individuals (= nurses—Ammen), by gemmation for 
the most part, sexual animals are produced and thrown off, 
which contain either male or female reproductive materials, 
and after swimming about freely for a certain time, reproduce 
the form of the parent animal by a sexual process. The 
budded offspring are not only different from the parent ani- 
mals, but the males and females differ from each other. 
With regard to the second point, I would in the first place 
once more point out that Krohn was the first who pertectly 
recognized and declared the genetic connexion between the 
