CONCHOLOGY. oL> 
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. South American 
seas. One species. 
Tubicinella balenarum. 
2. Genus Coronula. Pl. V. 
Animal. Body seated, enveloped in a shell with small setaceous 
and cirrous arms. 
Shell. 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. Inhabits the North seas. Five species. 
Coronula diadema. Coronula balenaris. 
C. testudinaria. C. pulchra. 
C. denticulata.* 
3. Genus Balanus. Pl. V. 
Animal. Body sessile, inclosed in an operculated shell; 
branchie numerous, placed in two rows, unequal, articulated, 
cilliated ; each composed of two cirri, supported by a peduncle, 
and exsertile ; mouth with four transverse dentated jaws, with four 
hairy palpi-like appendages. 
Shell. Formed of six distinct coronary valves, one dorsal, one 
ventral, and two pairs of laterals, with a calcareous support; 
operculum forming a sort of pyramid, by four articulated pieces 
in the aperture of the shell. Is found in almost all seas. Thirty 
species. 
Balanus angulosus. Balanus calycularis. 
B. nigrescens. B. subimbricatus. 
B. roseus. B. palmatus. 
B. amphimorphus. B. dupluconus. 
B. crispatus. B. semiplicatus. 
B. stalaciferus. B. levis. 
B. patellaris. B. punctatus. 
