CONCHOLOGY. 31 



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 balaenarum. 



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 balaenaris. 



C. testudinaria. C. pulchra. 



C. denticulata.* 



3. Genus Balamis. PI. V. 



Animal. Body sessile, inclosed in an operculated shell; 

 brancBiae 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. laevis. 



B. patellaris. B. punctatus. 



