Dr. W. C. M‘Intosh on the Boring of certain Annelids. 283 
this species (in all probability), which he termed Spvo seti- 
cornis. He observed that the tentacles, when seizing a frag- 
ment of oyster, attached themselves to it ‘not by winding 
themselves round it, but by simple adhesion, as if they were 
studded with numerous suckers and hooks, like the arms of the 
cuttle-fish.”” This prehensile apparatus “ consists of numerous 
large papille thickly crowded together along the borders of 
the tentacles,” each having an “ acuminated soft cilium or 
spine.”’ On forcibly pressing the tentacle, “ the spine-bearing 
papille burst, and there issues from each of them a.... pear- 
shaped capsule (trichocyst).... which, again, on rupture, dis- 
charges a multitude of acicular spicules.” He likewise states 
that the tentacles are furnished with ‘a ciliated band running 
from the tip to the base,” but does not point out the actual 
disposition thereof. In his drawing of the tentacle (fig. 18) 
the papille are ranged along each side of the organ from base 
to apex. 
When the tentacle is extended, as in its ordinary motions 
(Pl. XIX. fig. 1), there is little or no appearance of wrinkles. 
A very considerable alteration, however, ensues on placing the 
animal, even without irritating pressure, between glasses, and 
certainly much more so if the tentacle itself is removed by 
violence. The ciliated groove along the inner border, like the 
rest of the organ, is minutely granular, especially towards the 
tip, the latter, on the slightest contraction, assuming a minutely 
warty aspect (fig. 2). Besides the long cilia which cover the 
furrow, there are various motionless hairs along the opposite 
or exterior border of the organ, as indicated by Prof. Keferstein, 
and which are also present on various other parts of the animal. 
The wrinkling of the tentacles in most views is very marked, 
the whole organ being crossed by transverse seams, between 
every two of which a series of very distinct temporary papille 
occur at the edge, which papille sometimes do possess a mo- 
tionless cilium or “ spine,” and are more likely to do so under 
paralyzing pressure ; but the appearance shown by Dr. Wright 
is the result of injury, and not a natural interpretation of their 
anatomy, however closely his outline may indicate what he 
saw. ‘These temporary papille, in common with the entire 
surface of the furrow, certainly present a streaked appearance; 
but such is due to the compressed cilia; and I have never been 
able to see the remarkable “ trichocysts” and their acicular 
contents as described by this mgenious naturalist, to whose 
observations I gave due respect by repeated examinations. 
Circular cells filled with minute granules often escaped through 
the delicate epiderm of the pressed organ, together with mi- 
nute granules and swarms of discarded cilia; but there was no 
