3 
Ztnti) Clajsss; 
CXRRHIPEDA. 
Shell sessile or elevated, on a flexible, tendinous pedicle ; multivalve ; sometimes moveable, 
sometimes fixed; the inside covered by the Mantle of the Animal. 
The cirrhipeda 
are divided into Two Orders.. — . — .Sessile Cirrhipeda, 
Pedunculated Cirrhipeda, 
and 
ORDER I SESSILE CIRRHIPEDA* 6 Genera. 
THE Shells of this Order are fixed on marine bodies. 
Tubicinella. — S hell univalve, operculated, tubular, erect, a little attenuated towards 
the base, bound with annular transverse ribs, truncated at both ends, open at the 
summit, and closed at the base with a membrane. Operculum with four obtuse 
valves. 
Plate I. Fig. 12. T. balfenarum. 
Coronula. — S hell sessile, apparently indivisible, suborbicular, conoidal or blunt-conical, 
the extremities truncated, the sides very thick, the inside hollowed into radiating 
cells. Operculum composed of four obtuse valves. 
Plate I. Fig. 13. (a) C. balsenaris. Upper-side. (Lepas balsenaris. — Linn.) 
( b ) Inside. 
Balanus. — S hell sessile, fixed, conical, summit truncated, closed at the base by an ad- 
hering testaceous lamina. Aperture subtriangular, or elliptical. Operculum inter- 
nal, quadrivalve, the valves moveable, inserted near the base of the inside of the 
shell. 
Plate I. Fig. 14. B. radiatus. 
Acasta. — S hell sessile, oval, subconical, composed of separable pieces : cone formed of 
six unequal lateral valves united together; the base a lamina or orbicular valve, 
concave on the inside, resembling a patella or little cup. Operculum quadrivalve. 
Plate I. Fig. 15. A. Montagui. 
* Lamarck has erroneously separated this Order into Two Divisions — Operculum quadrivalve, and Oper- 
culum bivalve. Sowerby has shewn, in his Genera, that the whole are quadrivalve. 
B ^ 
