ORDER III. ABRANCHIA. 249 
tifully colored of animals. “Its form is oval, six or eight inches long, and 
two or three broad. The scales of its back are covered and concealed by ¢ 
substance resembling tow, which originates at its sides : the latter have also 
groups of stout spines, which partly pierce the tongue, together with 
bundles of flexible bristles, as brilliant as gold, and changeable to every hue 
of the rainbow. The colors they present are surpassed in beauty neither by 
the scale-like feathers of the humming-bird, nor by the most brilliant gems. 
Below them is a tubercle bearing three groups of spines, of three different 
thicknesses, and finally a fleshy cover. There are forty of these tubercles 
on each side, and between the two first are two little fleshy tentacles; be- 
sides which there are fifteen pairs of broad scales, which are sometimes 
bulged upon the back, and fifteen small branchial crests on each side. 
“The animals of this group, which greatly resemble, in form, the Lu- 
phrosine laureata, are well known under the name of Sea Mice, and are 
often thrown upon the beach after a gale of wind. In some species the 
lateral sete exhibit a beautiful structure, admirably fitting them for weapons 
of defence, being barbed on each side at the tip; but, in order to prevent 
the injury which might occur to the animal in consequence of the power it 
possesses of retracting these seta, each is enclosed in a smooth, horny sheath, 
composed of two blades.” 
ORDER III. ABRANCHIA. 
hese Annelides have no respiratory organs appearing externally, and 
seem to breathe either, as in the earth-worms, over the whole surface of the 
skin, or, as in the leeches, by internal cavities. Some have bristles, which 
serve for locomotion, and others are not thus furnished; and from this 
peculiarity they are divided into two families —the Lristled and the Un- 
bristled. 
First Famity. — This comprises the Earth-worms, or Nereides of Lin- 
nus ; they are provided with silky bristles, have a long, cylindrical body 
divided by transverse furrows into a great number of rings, and a mouth 
without teeth. The genus 
Lumpricus may be regarded as a fair representative of the whole family. 
L. terrestris, the common Earth-worm, is a well-known species, which 
often attains to quite a foot in length, with one hundred and twenty rings. 
There are two pores under the sixteenth ring, the purpose of which has not 
been discovered. It mines the ground in all directions, piercing it with 
great ease, in search of the roots and animals on which it subsists. In the 
month of June it seeks the upper world at night, and searches for a com- 
