Dr. W. C. M‘Intosh on the Boring of certain Annelids. 285 
The inferior appendages of the rest of the body-segments 
consist of characteristic hooks—organs, I may add, that have 
received but scant justice from their artists, with the exception 
of M. Claparéde* and Mr. Agassiz, though the latter appears 
to have slightly misapprehended their true nature, as he speaks 
of “a stiff bristle extending from the base of the curve’’—which 
can only refer to the wing of the structure, about to be de- 
scribed. The figure} of this careful observer, though earlier, 
is more correct than Mr. Lankester’s. When the hook is pressed 
flatly between glasses (Pl. XVIII. fig. 4 a), the crown shows 
a long tooth in front, with a shorter superior process and a dis- 
tinct wing; but the latter, of course, has been altered by pres- 
sure, as, when viewed under favourable circumstances (fig.4 5), 
it has a wing on each side of the crown and upper part of the 
shaft. Dr.’Thomas Williams was in error when he assigned 
a dorsal position to these hookst. The bristles throughout 
conform to one type (fig. 5), having a long shaft, somewhat 
abruptly bent and tapered at the tip, which has a narrow pro- 
cess or wing on each side. 
The anal segment is furnished with a peculiar cup (fig. 6), 
whose margin does not form a continuous ring, but is inflected 
and slit in the middle of the dorsal surface. A few minute 
and motionless cilia are placed round the margin. The papilla 
of the anal orifice is richly ciliated. The organ does not im- 
press the observer as being eminently adapted for adhering to 
surfaces, after the manner of a sucker; nor have I been so 
fortunate as to see the animal using it for this purpose. Mr. 
A. Agassiz and MM. Claparéde and De Quatrefages, however, 
have seen the Annelid employing it for such ; and M. Meczni- 
koff§ is another author who mentions that a “ sucking-disk ”’ 
is met with in Leuwcodore. Dr. Williams, again, remarks that 
the anal segment is expanded with geometrical exactitude into 
a hollow cone, which acts on the principle of the sucker, the 
worm “letting down its weight on the part, in order to press 
companying this paper. He said that, instead of one spur, there were 
several spurs beneath the curved tip. Ofcourse I have found no reason to 
alter an opinion formed after an examination of specimens from the north, 
east, and west of Scotland, from the north-east, south, and south-west of 
England, and from the Channel Islands. Mr. Agassiz and Prof. Kefer- 
stein, moreover, show only one process; and though M. de Quatrefages 
represents at least two beneath the tip of the hook of his Lewcodore nasuta 
from Bréhat, Iam bound to add that many of this distinguished author's 
drawings are not scientifically accurate. I do not know on what authority 
my friend made his statement; and it is to be hoped he will clear up the 
mystery. * Archiv fiir Anat. u. Phys. 1861, Taf. 15. 
+ Ann. Nat. Hist. ser, 3. vol. xix. pl. 6. fig. 38. 
t Report Brit. Assoc. 1851, p. 208. 
§ Zeitschr. fiir wiss. Zool. Bd. xvi. 
Ann. & Mag. N. Hist. Ser.4. Vol. ii. 20 
