ON KYNOTUS CINGULATUS. AD57 
The penial cheta of Kynotus, in fact, resembles the 
cheetze of several Polycheta in this respect, and I am not 
aware that this feature has been noted previously in Oligo- 
cheeta. 
With regard to the prostate, or spermiducal gland, it has 
the structure so frequently described for many earthworms ; its 
lumen is surrounded by a layer of narrow columnar cells: this 
is surrounded by a very thin coat of circular muscle, which 
is traversed by the narrow necks of the great club-shaped 
gland-cells (fig. 16). In a transverse section of the entire 
gland (fig. 15), the limits of the various loops of the coil 
are not by any means well defined; one sees two or three 
ducts apparently embedded in a mass of glandular tissue, and 
the whole surrounded by a sheath of muscle, in which run 
blood-vessels. Closer examination generally enables one to 
trace the outline of the groups of gland cells belonging to 
each section of the duct. 
The clasper (figs. 17—20).—I have already described the 
appearance of this peculiar organ when protruded. 
In the worm which was dissected, in which the “ clasper” 
was entirely retracted, there was seen lying in segment xv 
(the 25th ring) an irregularly oval body, convex upwards, 
with a very irregular surface; its long axis is parallel with 
that of the worm’s body (S., fig. 7). This is the structure 
which Michaelsen terms “bursa propulsoria.””? What appear- 
ance it would present from within when completely everted I 
am unable to say: whether the whole structure is capable of 
being protruded or not is at present unknown. 
This “bursa propulsoria,” or retracted ‘“ clasper,” is larger 
than the segment to which it belongs, and pushes apart the 
septa in front and behind. Its external opening is of course 
invisible from within, as it lies below the organ. 
From its outer side there arises a muscle (fig. 7, m.) which 
passes forwards, and becomes continuous with the longitudinal 
muscles of segment xtv. This is called by Rosa the “ re- 
tractor muscle.”’ At the hinder end of this organ there arises 
from its ventral surface, a gland (fig. 7, pr*.), exactly like those 
