[ 483 [ 
XXII. On a Species of Chsetopterus (C. insignis, Baird) from North Wales. By Joun 
WILLIAMS, Esq. Communicated by W. BAIRD, M.D., F.L.S., &e. 
(Plate XLIX.) 
Read May 5th, 1864. 
Beaumaris, April 26, 1864. 
DEAR SIR, 
I HAVE forwarded to you a case, containing eight specimens of Chetopterus in spirit. 
I trust they will reach you in safety, and turn out to be properly preserved*. I took pains 
to fill every tube with spirit. 
I first met with this Annelid here in December 1859, and have since found plenty of 
them. In one spot especially they abound. I find them in hard smooth sand and 
gravel, among boulders. They lie very far down, and can only be obtained on a low 
spring ebb. 
Both ends of the tube project from half an inch to a couple of inches above the surface 
of the ground; but they are often hidden by tufts of seaweed growing onthem. The two 
ends are usually about a foot apart. I make it a rule to find both ends before I begin to 
dig, or else I should probably cut the tube in two. When therefore many tube-ends are 
to be seen, great caution is necessary. 'Two appearing within 6 inches of each other 
indicate two tubes, unless they are very small. 
1 find great variety of size: some tubes are not above 8 inches long, and lie with their 
ends not 3 inches apart; others are more than 2 feet long, and broad in proportion. 
In both the Annelid is precisely the same in every respect, except size; and I have always 
found the same parasite in either tube, but smaller in a small tube. 
There isa specimen of Chetopterus pergamentaceus in the Derby Museum at Liverpool, 
which, by the favour of Mr. Moore, I have examined. The tube there is much tougher 
and more like parchment than those I find here; but it has no adherent gravel. Here 
they are thickly covered with gravel and small stones. The tubes are made of the horse- 
shoe-form, in which they lie in the earth; and they cannot be stretched out straight 
without tearing the upper side. I have found one passing under a large stone, with one 
end appearing at each side of it. It is not unusual, when two tubes lie very near together, 
to find them adhering; but I never find any communication between them. So some- 
times a tube is found which has a short length of similar structure fast to it. Here also 
I find no communication ; and the extra length, having only one outlet, is always disused 
and full of sand. 1 
On one occasion I spent fully half an hour watching the tubes in situ while there was 
a few inches of water still flowing over them. I saw no movement whatever : no head 
Projected, no apparent flow of water into or out of them, and no sign of their being 
[* These specimens are now in the British Museum,—W. B.] 
