CIRRIPEDA. 
Adna. 
237 
Genus I.—BALANUS.— Lamarck. 
Shell sessile, conical, or subconic, closed at the base by a 
testaceous plate, which adheres to extraneous substances, con- 
consisting of fouf articulated valves; aperture subtrigonal, or 
elliptical, and shut by an operculum composed of four valves. 
1. Balanus tessellatus. —The Chequered Balanus, pi. 
XCVIL fig. 49. 
B. tessellatus. Sowerby, I. p. 193, pi. 84, fig. 1. 
Obliquely conical, thin, with six obscurely ribbed, smooth 
valves; interstices finely tessellated; aperture oval, its longest 
diameter being about half an inch high, somewhat less than 
its basal diameter. 
Mammiferous Crag, Bramerton, Norfolk. 
2. Balanus crassus. —The Thick Balanus, pi. XCVII. fig. 
52 to 50. 
B. crassus. Sowerby I. p. 194, pi. 84, fig. 2, 3, 4. 
Oblique, thick, with six smooth, obscurely ribbed valves; 
aperture triangular. 
The Coralline Crag, Ramshot, and the Red Crag, Sutton. 
3. Balanus balanoides. —The Acorn Balanus, pi. XCVII. 
fig. 49. 
B. balanoides. Brown, Ill. Rec. Conch. Brit. p. 120, pi. 
53, fig. 17 and 54, figs. 4, 5. 
Sub-conic, sub-depressed, smooth ; aperture wide ; operculum 
with the two anterior valves slightly striated transversely; the 
posterior ones smooth. 
The Raised Beaches, Bute, &c. 
4. Balanus communis. —The Common Balanus, pi. XCVII. 
fig. 63. 
B. communis. Brown, Ill. Rec. Conch. Brit. p. 120, pi. 53, 
fig. 23, and pi. 54, fig. 1. 
Strong rugged, conic, compartments unequal, with many 
irregularlongitudinal squamous ribs; the interstices transversely 
wrinkled; aperture contracted. 
The Red and Coral Crags, Sutton, and the Raised Beaches, 
Clyde, &c. 
5. Balanus costatus. —The Ribbed Balanus, pi. XCVII. 
fig. 02. 
B . costatus. Brown, Ill. Rec. Conch. Brit. p. 120, pi. 54, 
figs. 2, 3. 
Sub-conic, depressed; nearly circular at the base ; with from 
seventeen to nineteen nearly equidistant, divergent, smooth 
ribs; all of which extend considerably beyond the basal margin; 
aperture small and sub-ovate. 
The Raised Beach, Clyde. 
0. Balanus punctatus. —The Punctured Balanus, pi. XCVII. 
fig. 58. 
B. punctatus. Biwn, Ill. Rec. Conch. Brit. p. 121, pi. 53, 
figs. 5, 6, 13, 20. 
Sub-conic, with indistinct compartments; generally with 
numerous longitudinal, narrow ribs, and several transverse 
irregular lines of growth ; aperture wide, rather plain on the 
edge, operculum puuctured. 
Raised Beach, Ayr. 
7. Balanus rugosus. —The Rough Balanus, pi. XCVII. 
fig. 57. 
B. rugosus. Brown, Ill. Rec. Conch. Brit. p. 121, pi. 53, 
figs. 4, 7, 8, and 21. 
Sub-conic, divided into six compartments by irregular in- 
equidistant furrows; those of the posterior side broadest, and 
crossed by deep divisions, formed by the lines of growth; 
these are sometimes wrinkled or striated, longitudinally; aper¬ 
ture very large; inner margin transversely ridged. 
Raised Beaches, Clyde, &c., and the Coral Crag, Sutton. 
8. Balanus tintinnabulum. —The Little Bell Balanus, pi. 
XCVII. fig. 00. 
B. tintinnabulum. Donovan, Brit. Sh., pi. 148. 
Obtusely sub-conic, with three raised compartments, con¬ 
tracting to a point upwards, and longitudinally striate, and 
three depressed ones, contracting to a point downwards, and 
transversely striate; aperture rather wide. 
The Raised Beaches, Scotland, and Norfolk. 
9. Balanus spongeosus. —The Sponge Balanus, pi. XCVII. 
fig. 51. 
B. Spongeosus. Montague, Sup. p. 2, Acasta Montagui. 
Leach. 
Ovate, with six angulated compartments, their points extend¬ 
ing considerably above the margin of the aperture; three anterior 
divisions, broader, and not so long as the posterior ones ; external 
surface wrinkled, and provided with numerous spiuiforrn pro¬ 
cesses; apcrculum four-valved, the anterior pair with strong 
regular, deep, but narrow ridges, crossed by longitudinal striae ; 
internal margins deeply serrated; posterior pair longer than 
the others, with their points sharp, and considerably arcuated ; 
base of the shell, cup-shaped. 
The Coral Crag, Sutton. 
Genus II.—ADNA.— l^each. 
Shell consisting of an upper valve, supported on a funnel- 
shaped base, which is not sunk in the substance to which it is 
attached, but is seen externally, the operculum consisting of 
four valves. 
I. Adna sulcata. —The Furrowed Adna, pi. XCVII. f. 59. 
Wood pgrgoma. Phillipi En. Mol. Sicily, p. 252, pi. 12, 
fig. 24.. 
Sub-conic, with many longitudinal plain ribs ; aperture wide. 
The Coral Crag, Ramshot. 
3 B 
