132 ANNELIDES. SEDENTARY. 



S. vermicularis, Lin. Shell creeping, taper, subulate, curved, and 

 transversely wrinkled, sometimes subcarinated, Inhabits coasts 

 of Europe, on stones and shells. B. Brown's Illust. pi. 2, fig. 2, 3. 



S. glomeraia, Lin. Shells taper, with decussated wrinkles, twisted, 

 and in large masses. Indian seas. Bonan. 1, pi. 20, fig. E. 



S. vermicella, Lam. Shells filiform, round, transversely rugose, flexu- 

 ose, and forming a thick mass. Favanne, pi. 6, fig. B. 

 Fossil species of Serpulag are found in France and Italy. 



Gen. 5. SPIRORBIS, Lam. Serpula, Lin. 

 Body tubicular, subcylindrical, attenuated posteriorly ; six pin- 

 nated retractile branchiae, disposed in rays at the anterior ex- 

 tremity; operculum between the branchiae. Tube testaceous, 

 twisted spirally into an orbicular form, flattened and fixed 

 below. 



The animals of this genus are always found fixed upon fuci, shells, and other ma- 

 rine bodies, often in great numbers, but always isolated. The opening of the tube 

 is terminal, rounded, sometimes trigonal. The animal is of a blood-red colour. 

 S. nautiloides, Lam. (S. spirorbis, Lin.) Shell discoid, subumbi- 



licated, the whorls rounded above, slightly rugose, and gradually 



tapering to a point. 1 line in diameter. Inhabits European seas, 



on fuci Pen. Brit. ZooL pi. 94, fig. 1. 



S. spirillum, Lam. Shell regular, spiral, orbicular, and pellucid ; 

 whorls taper. Very small. Inhabits European seas on Sertula- 

 rice, &c. B Brown's Illust. pi. 1, fig. 41, 42, 53, 54. 



S. lamellosa, Lam. Shell discoidal, subumbilicated, the whorls with 

 longitudinal, lamellar, denticulated ribs, and the interstices striat- 

 ed. Inhabits seas of New Holland. Lam. v. 359. 



FAMILY II. AMPHITRTT^A. 



Branchiae not separate or covered by an operculum, and dispos- 

 ed towards the anterior part of the body. Tube membranous 

 or horny, more or less arenaceous. 



The animals of this family live in membranaceous or coriaceous tubes, more or less 

 incrusted exteriorly with grains of sand and fragments of shells, and open at the an- 

 terior extremity. The branchiae are placed at or near the anterior extremity, some- 

 times large and projecting above the mouth, sometimes short, in the vicinity of the 

 mouth, or below it. Maay have tentacula, but all are destitute of eyes, proboscis, 

 and jaws. All the groups are furnished with pediform retractile papillae on the sides, 

 with bundles of subulate bristles, and hooked retractile setae. 



* Branchice or tentacula large. 

 Gen. 6. AMPHITRITE, Lam. 



Body tubicular, elongated, cylindrical, attenuated posteriorly, 

 and in numerous segments, with a row of setiferous papillae, 

 subulate bristles in bundles, and hooked setae ; branchiae ter- 

 minal, in slender digitations disposed like a fan spreading 

 into a disc ; two short subulate filaments inserted at the in- 

 ternal base of the branchiae ; mouth terminal, between the 

 branchiae. Tube elongated, cylindrical, tapering toward the 

 base, membranous or coriaceous, generally naked. 



