. A catalogue of the British non-parasitical worms in the collection of the British Museum. Worms. NORTHIA. 137 The worm lives in a tube which has a singularly exact resemblance to the barrel of a quill. It is about 4 inches long, and the upper portion is thinner than the lower, which is tough, and not easily cut with a knife. 1 made a vain attempt to form it into a pen. No. XX.—Northia tubicola. W. 1 a. Cephalic segment with three long subulate tentacula. 1 8i 2 a, b. Tentacular cirri. 2 c. The mouth, upper lip, formed of two large egg-shaped tubercles. 3. Section of anterior part of body, sh
. A catalogue of the British non-parasitical worms in the collection of the British Museum. Worms. NORTHIA. 137 The worm lives in a tube which has a singularly exact resemblance to the barrel of a quill. It is about 4 inches long, and the upper portion is thinner than the lower, which is tough, and not easily cut with a knife. 1 made a vain attempt to form it into a pen. No. XX.—Northia tubicola. W. 1 a. Cephalic segment with three long subulate tentacula. 1 8i 2 a, b. Tentacular cirri. 2 c. The mouth, upper lip, formed of two large egg-shaped tubercles. 3. Section of anterior part of body, showing the cirrus above and below the foot. 4. A spine, one on each fascicle of the foot. 5. Forceps, two on each fascicle of the foot. 6. Lanceolate bristles, many on each foot, curved at the tip, and very sharp and double-edged at the point of curvature. Let us see if, in its curious structure, we can find a key to the habits of the animal. We learn from Miiller that it lives in soft mud, and one unceasing object of its life is the capture of prey. For this end, it must protrude the anterior portion of the body beyond its tube, and raise itself above the surface of the mud,—and remain, in this position, on watch. To enable the worm to do this with ease, is, I conjecture, the office of the forceps-like bristles of the feet: with their ends, it may hook itself to the rim of the tube, and thus obtain a support without the waste of muscular power, A long watch is thus rendered less irksome, while at the same time the capacity to seize upon a passing prey is increased. The prey caught, analogy leads us to conclude that the worm will instantly retreat and sink within its tube, where it can feed without disturbance or fear. But as the entry and passage are narrow and unyielding, it seems to follow that the prey should be held by the mouth alone when in the act of being dragged within the tube, and. Please note that these images are extracted from scanned page images that may have
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectworms, bookyear1865
