392 



Div. 3. ARTICJULATA.— ANNELIDES. 



Class 1. 



like the antlers of a stag'. This is the Tcrebella bicornes, Abeldg., and the Actinia or Animat-ftuwer of Home. 

 M. Savigny has made of it his subdivision of Scrpiiles cymospires, \s\uc\\ ^I. Blainville elevates to the rank of 

 a g'enus. 



M. Laraarck distinpruislies the Sj)irorbis, the branchial filaments of which are much less nimierous (three or 

 four only on each side) ; their tube is of a tolerably regular spiral form, and they are mostly very small : such is 

 S. spirellum, Pallas, and S. spirorbis, MuUer. 



Sabella, Cuv. {AmpJdtrite, Lam.) 

 The same body and fan-like gills as in Serjnda, but with the fleshy filaments adhering to tlie bran- 

 chiae, pointed, and neither of them forming an operculum ; they arc also not always present. Their 

 tube appears oftener composed of granules of clay or very fine mud, and is rarely calcareous. The 

 known species are rather large, and their branchial tufts are of an admirable delicacy and beauty. 



Some, like the SerpuLe, have on the anterior portion of the back a membranous disk, across which pass the first 

 pairs of their bundles of bristles ; their branchial pectinations are turned spirally, and their tentacles reduced to slight 

 folds. They are the Serpiiles spiramelles of M. Savigny, and the iSpiramilla, Blainville. A large and beautiful 

 species inhabits the Mediterranean, with a calcareous tube like that of the Serpula, or orange-coloured gills, &c., 

 the 'S. proiula, Nobis, or Pastula Rudolphii, Risso. 



Others have no membranous disk on tlie foreparts, and their branchial pectinations form two equal spires, the 

 Sabcllcs simples of M. Savigny. Such are Amphritite reniformis, Muller, or Ttibularia penicilliis, Id. ; also Tere- 

 bella reniformis, Gmelin, together with the Amphritite infundibulum, Montagu, and A. vesiculosa. Id. 



There are some with a double range of filaments on each pectination— the Sabella: Astartcc, Sav., such as S. 

 ffrandis, Cuv., or S. indica, Sav., and the Tubularia magnifica, Shaw. 



Others in which one pectination only is twirled, the others being smaller, and enveloped within the base of the 

 first. The Sabellcs spirographes, Sav., as S. unispira, Cuv., and SpirograpMs Spallanzani, Mart. 



In some the gills do not form a simple funnel round the month, but numerous filaments, which are serrated and 

 strongly ciliated on the internal face; the silky feet of these are almost imperceptible— such is /S. villosa, Cuv. 



Lastly, some have been described with six filaments disposed like a star — the Fabricia of Blainville. 



Terebella, Cuv., — 

 Like the greater number of species of Sabella, inhabit a factitious tube, but which is composed of 



grains of sand, and fragments of shells ; their body lias 

 much fewer rings, and the head is difl'erently ornamented. 

 Numerous filiform tentacles, capable of much extension, 

 surround the mouth, and upon the neck are gills of an ar- 

 buscular, and not a fan-like form. 



There are several on our coasts which were long confounded 

 under the name of Tcrebella couchilega, Gm., and which are 

 mosty remarkable for having their tubes formed of large frag- 

 ments of shells, the aperture having its borders prolonged into several 

 small branches formed of the same fragments, which serves to lodge 

 the tentacles. 



The greater number have three pairs of branchiae, which in those with 

 branched tubes pass through a hole for the purpose ; they are the 

 Terebelles simples, Sav. 



Amphitrite, Cuv. — 

 Are easily recognized by their golden-coloured spines, disposed 

 in a com])-like series, or in a crown, in one or several ranges 

 upon the forepart of the head, and which probably serve them 

 for defence, or perhaps to crawl with, or to gather up the mate- 

 rials for the tube. Around the mouth arc very numerous ten- 

 tacles, and on either side of the commencement of the back are 

 pectinated gills. 



Some of them compose slight tubes, of a regular conical form, which they carry about with them. Their gilded 

 spines form two comb-like series, the teeth of which are directed downwards ; and the intestine is very ample, 

 and several times folded, being ordinarily full of sand ; they are Pectinaires of Lamarck, the Ampliyctincs, Sav., 

 the Clirysodons, Oken, and the Cislcna, Leach. Such, upon our coasts, is the A. belgica, Gmelin, with a tube 

 two inches long, formed of small round granules of various colours. A much larger species occurs in the Southern 

 seas, A. auricnma capcnsis, Pallas, the slender and polished tube of which appears as though transversely fibrous, 

 and formed of a soft fucus-steni-like substance, dried up. 



There are some species which inhabit factitious tubes fixed to various substances. Their gilded siiines form 

 several concentric crowns upon the head, whence results an operculum that closes the tube when they contract 

 into it, but which has two parts that can be spread asunder. They have a cirrhus ou each foot. Their body 



Fig. 200. — Tcrebella medusa, in its tube. 



Fig. 201. — Terebelld variabilis. 



