70 Lamarck’s Genera of Shells. 
AMPHITRITEA. (4 Genera.) 
Branchie, not separate nor covered by an operculum, dis- 
posed at or near the anterior part of the body. 
Tube membranous or horny, more or less arenaceous. 
1. Pectinaria*. 
Body tubular, subcylindrical, posteriorly attenuated, a row 
of bristly mammillez on each side; bristles short, fasciculated. 
Anterior extremity broad, blunt, oblique, with two transverse 
rows of very brilliant gilt paleee. Mouth elongated, bilabiate, 
surrounded with numerous short tentacula. Four branchie, 
disposed like the teeth of a comb, on the second and third 
segment of the body. 
Tube conical, inverted, membranous, or papyraceous, arena- 
ceous, not fixed. 
Type. Pectinaria Belgicat. 
Tube inverted, conical, membranous, mixed with small sand, 
about three inches long. European Seas. Pl.iii. Fig. 3. 
2 Species. 
2. Sabellaria ft. 
Body tubular, subcylindrical, posteriorly attenuated; a single 
row of awl-shaped fascicular sete on each side, besides spa- 
tulate setee, and transverse laminz fringed with hooked sete. 
Anterior extremity obliquely truncated, elliptical, crowned 
with six rows of very brilliant palee, three on each side; the 
external very open, the internal ‘erect almost approaching ; 
mouth elongate, fissure-shaped, bilabiate, situated below the 
anterior palez. Branchiee very small, composed of numerous 
rows of small flat threads, near the mouth. No tentacula. 
Tubes numerous, composed of agglutinated sand and frag- 
ments of shells, aggregated into a common mass, cellular on 
the upper side; orifices cup-shaped. 
Type. Sabellaria alveolata §, (Sabella alveolata. Linn.) 
Narrow tubes, at small distances, variously immersed in a 
depressed mass: openings cup-shaped. European Ocean. 
Pl. iii. Fig. 4. 2 Species. 
* Peeten, a comb. + Belgic. + From sabulum, coarse sand ? 
§ Channelled. 
