DR. BAIRD ON A NEW SPECIES OF BRITISH ANNELIDES. 481 
bilobed, while the others are divided into two separate portions, the free edges of which 
are beset with a row of short, straight, simple sete. The dorsal branch consists of a 
conical lobe (figs. 17 & 7), similar in appearance to the corresponding branches of the 
feet of the anterior portion of the body, but containing a fascicle of straight, simple, 
sharp-pointed, yellow and rather long setæ (fig. 8), which are iridescent. The segments, 
as well as the feet-peduncles, gradually diminish in size as they approach the extremity, 
the last six or eight segments being crowded together and very short. 
The whole animal (as seen kept in spirits) is of a light green or greenish-yellow colour, 
of a uniform hue, with the exception of the series of black set» on the fourth foot of the 
anterior portion, which give the appearance of a bright black spot, like an eye. 
The tube in which this animal dwells is about 13 inch in circumference, and extends 
in length from 1 foot to 20 inches. It is composed of a thin parchment-like substance, 
eovered externally with grains of sand and small pebbles, and smooth internally, but 
with which the animal has apparently no muscular adhesion or connexion. It is found 
in muddy sand at low water, lying horizontally on the mud, and frequently half buried. 
When of considerable length, it is bent like a siphon, with the two extremities free and 
projecting about an inch or so above the sand. 
C 
elopterus insignis does not appear to be rare, as it has been found in the Channel 
Islands, at Polperro in Cornwall, in the Firth of Clyde off the island of Cumbrae, and 
at Plymouth; and we have in the British Museum tubes without the animal, from 
Falmouth. 
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