P. H. GOSSE, _del._ LEIGHTON, BROS.
SABELLÆ.
]
One species of this genus[145] can by the cursory observer be
distinguished from the Serpulæ, only by this absence of the antennal
stopper. For it dwells in a shelly tube, essentially resembling those
which we have just been examining. It has peculiarities of detail,
however. It is never found associated with numbers of its fellows in
agglutinated groups, but always, so far as my experience goes, singly.
It is more common on shells than on stones, generally attached to the
old valve of some cockle or scallop. It is straight or nearly so, never
at least contorted. Attached only for a very short portion of its
smaller end, perhaps for an inch or so, for which it creeps along the
surface, it then rises into a more or less erect position, extending
sometimes to a height of seven or eight inches perfectly free. The tube
is of about the same diameter as that of the Serpula, but is slighter
in structure, or perhaps it appears so, because it is destitute of
those expansions which here and there in that species indicate the
trumpet-lips of successive stages of development. The extremity of the
tube here is simple, not expanding. Slight annular rings, however, do
here and there vary the shelly surface of the tube.
The gill-tufts are ample; they are two, considerably infolded,
consisting of about forty-five filaments each, which are much longer
and slenderer than those of the Serpula, the last filaments of the
volutions diminishing rapidly. The secondary filaments, or pinnæ, are
very fine and very numerous, so set on the main stem that the two
rows form the sides of a narrow groove, facing inwards. The whole
is yellowish-white with eight or ten bright scarlet dots set with
intervals all along the back or outer side of the stem. When fully
protruded, the base of the gills, and even a good deal of the neck,
lolls out of the tube. If the animal be removed, the body is seen to
be white, elegantly banded with scarlet, and furnished with a broad
translucent collar, edged with scarlet: this collar ordinarily lines
the mouth of the tube.
From the length and isolation of its shelly tube this is a remarkable
species: the great tenuity of its filaments, however, requires a lens
to bring out their beauties; but with this aid, the arrangement of the
rich scarlet bands and spots on the pale yellow ground cannot fail to
evoke admiration.