TUBICOLiE. 
391 
siders them as the intermediate link between the Vertebrata and Annulosa, ob- 
serving upon the curious circum- 
stance that these two subkingdoms, 
so highly organized in the scale of 
the creation, should be linked to- 
gether by a group exhibiting such 
great imperfections of structure. 
This class has been greatly neg- 
lected in this country. Dr. Johnston has, however, described various species (especially 
in the Annals of Natural History, for February, 1840), and Mr. Mac Leay, in the same 
number,* has noticed several fossil species. It is, however, in France that the greatest 
attention has been paid to them, especially by Savigny, Audouin, and Milne Edwards.] 
Fig. 19S. — Syllii moniJaris, with one of its locomotive organs and setigerous 
appendage attached thereto. 
THE FIRST ORDER OF ANNELIDES. 
THE TUBICOL^. 
Some species of this division form a homogeneous, calcareous tube, which probably results 
from their transudation, like the shells of the Mollusks, but to which the muscles do not adhere ; 
others construct tubes, by agglutinating grains of sand, fragments of shells, and particles of 
mud, which they join by means of a membrane, which likewise is doubtless transuded j lastly, 
there are some, the tubes of which are entirely membranous, or horny. 
To the first group belong 
Serpula, Linn., — ■ 
The calcareous tubes of which invest, from their twisting about, fragments of stones, shells, and all sorts of 
submarine matters. The truncation of these tubes is either round or angular, according to the species. 
The animal within has its body composed of a great number of segments ; its fore-part widened 
into a disk, furnished on each side with many bundles of stiff bristles ; and on either side of its 
mouth is a tuft of fan-like gills, in general vividly coloured. At the base of each tuft is a 
fleshy filament ; and one of these, on the right or left side indifferently, is always prolonged and di- 
lated at its extremity into a variously-formed disk, which serves for an operculum and mouth at the 
entrance of the tube when the creature retires into it. 
The common species {S. contortuplicata, Ellis), has a round and twisted tube three 
lines in diameter. Its operculum is funnel-shaped, and its gills often of a fine red, or 
varied with yellow, violet, &c. This animal quickly fabricates its tube of mud, aggluti- 
nating into it whatever small objects lie around. 
There is another and smaller species on our coasts, with a club-shaped operculum, 
armed with two or three little points {S. vermicular is, Gmelin). Its gills are sometimes 
blue. Nothing is more beautiful to see than a group of these Serpulae when their wings 
are expanded. 
In other species, the operculum is flat, and bristled with more numerous points. 
These are the Galeolaria, Lamarck. 
There is one in the Antilles (<S. gigantea, Pallas), w'hich is found among the Madre- 
pores, and the tube of which is often inclosed in their mass. Its gills roll up spirally 
when they are withdrawn, and the operculum is armed with two little bi'anching horns 
the memoir noticed above. 
Fig:. — S. contortuplicata, 
taken out of its tube. 
j Nereidina. . . . Animals free, having a distinct head, provided with eyes, or antennae, or both. 
L Serpulina Anira.als sedentary, and having no head, provided with eyes or antennae. 
* Mr. Mac Leay has given the following quinarian distribution of the class i 
ANNELIDA. 
Normal Group. 
Polypoda. 
Marine animals, having their body 
provided with distinct feet. 
Abbrran r Group. C Lumbricina .. Animals without eyes or antennae ; body externally setigerous for locomotion ; articula- 
I tion distinct. 
, , ... J Nemertina .. Animals aquatic, without eyes or antennae ; body not externally setigerous ; articulation 
Body without feet, or a distinct 'S indistinct 
j Hirudina.... Animals provided generally with eyes, but not with antennie ; body not externally seti- 
gerous ; articulation distinct. 
