STRUCTURE OF GLANDULAR VENTRICLE OF SYLLIS. 477 
transverse line of granules which does not in any way inter- 
rupt the continuity of the fibrils. 
By the action of acetic acid interfibrillar substance is brought 
into view in the form of narrow longitudinal lines of fine 
granules which sometimes extend without interruption through 
the bright disc. The same reagent also reveals in the sub- 
stance of the fibre star-shaped bodies with numerous exces- 
sively fine processes. 
On transverse section the fibres (fig. 4) present well-marked 
Cohnheim’s arezw, which appear finely granular, this granula- 
tion being evidently the expression of the fine longitudinal 
striation of the fibrille. 
The granular matter in the core of the fibre is coloured red 
in the fresh state, like nearly all the protoplasmic elements of 
the body of the annelid. Inthe form now under consideration 
(Syllis a) the relations of this granular matter to the differen- 
tiated muscle-substance which encloses it were not clearly 
made out, but in another species (Syllis (3) the granules of the 
core towards the inner end of the fibre are seen to become 
arranged in longitudinal rows, and these, when traced onwards, 
are found, by coalescence of the rounded granules, to become 
converted into homogenous muscle-fibrille. 
Syllis a has the transverse striations much more numerous 
and more strongly marked than any of the other species I 
have examined. In Syllis 6 and y (figs. 12 and 13) the 
striations are fairly distinct, but are few in number, half a 
dozen or so in the length of a fibre; the fibre has a single 
longitudinal cleft, and therefore presents a C-shape in trans- 
verse section. The protoplasmic core is reddish yellow. 
It is worth noting that this observation is in partial accord 
with the view of the constitution and development of striated 
muscle recently put forward by Wagener. [See Hofmann u. 
Schwalbe’s ‘ Jahresbericht,’ Band ii, and Pfliiger’s ‘ Archiv,’ 
Band xxx, 8. 511—535.] 
In Syllis 6, some of the fibres are not distinctly striated ; 
in other fibres the transverse marking is distinct enough—the 
strie being much more numerous and closer together than 
VoL, XXVI, PART 3,—NEW SER. Lg 
