Order 1. 



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- 

 ''v ^^^^^1 ^^J^' ■^^^^^* ■^^'^ gether by a group exhibiting such 



^'^'^jX^^' '^W'P great imperfections of structure. 



F.,.i93.-svm,mo„iuris.wuh^one^on^ This ckss has bccn 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 Savignjs Audouin, and Milne Edwards.] 



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 MoUusks, 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 ; 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 riglit 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 (&'. contorttiplicaia, 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 {.?. vermicularis, 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. giganiea, Pallas), which is found among the Madre- 



Fig. 199.— s. contortupiicata, 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 branching horns 



taken out of its tube 



* Mr. Mac Leay has given the following qninarian distribatiou of the class in the inemuir noticed above, 



ANNELIDA 

 Normal Geoup 



foypoa . . f Nercidina Animals free, havine a distinct head, provided with eyes, or antennae, or both. 



Marine animals, having their body ■( ^ ,^ ,_:_..,. .„^_ ..,,,_..: ,,._j ^j.j „^.i. „„, ,„„..„ 



provided with distinct feet. 



AbRKRANT (iBOUP. 



tion distinct. 

 '*'' • I Ncmertina .. Animals aquatic, without eyes or antenna; ; body not externally setigerous ; articulation 



indistinct. 

 Hirudina .... Animals provided generally with eyes, but not with antenniE ; body not externally eeti- 

 gerous ; articulation distinct. 



^_ Serpulina Animals sedentary, and having no head, proWded with eyes or antenitlE. 



Lumbricina. . Animals n-ithont eyes or antenna; body externally setigerous for locomotion ; articaln- 



Body without feet, or a distinct 

 head. 



