Adna. 



CIRRIPEDA. 



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 four articulated valves ; aperture subtrigonal, or 

 elliptical, and shut by an operculum composed of four valves. 



1. Balands tessellatus. — The Chequered Balanus, pi. 

 XCVII. fig. 40. 



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 thau 

 its basal diameter. 



Mammiferous Crag, Bramerton, Norfolk. 



a. Balands ckassus. — The Thick Balanus, pi. XCVII. fig. 

 52 to 56. 



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, Eamshot, and the Red Crag, Sutton. 



3. Balanos balanoides. — The Acorn Balanus, pi. XCVII. 

 fig. 49. 



B. balanoides. Brown, 111. Rec. Conch. Brit. p. ]2ii, 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 coitmunis. — The Common Balanus, pi. XCVII. 

 fig. 63. 



B. communis. Brown, 111. Rec. Conch. Brit. p. 120, pi. 53, 

 tig. 23, and pi. 54, fig. 1. 



Strong rugged, conic, compartments unequal, with many 

 irregular longitudinal squamous ribs ; the interstices transversely 

 wrinkled ; aperture contracted. 



The Red and Coral Crags, Sutton, and the Ptaised Beaches, 

 Clyde, &c. 



5. Balanus costatus. — The Ribbed Balanus, pi. XCVII. 

 fig. 62. 



B. costatus. Brown, HI. 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. 



6. Balanus puNCTATus.—ThePunctured Balanus, pl.XCVII. 



fig. 58. 



B. punctatus. Brown, 111. 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 

 u-regular lines of growth ; aperture wide, rather plain on the 

 edge, operculum punctured. 

 Raised Beach, Ayr. 



7. Balanus eugosus. — The Rough Balanus, pi. XCVII. 

 fig. 57. 



B. rugosus. Brown, 111. 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 tiktinnabulum. — The Little Bell Balanus, pi. 

 XCVII. fig. CO. 



B. tintinnahulum. 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 spiniform pro- 

 cesses; aperculum four-valved, the anterior pair with strong 

 regular, deep, but narrow ridges, crossed by longitudinal strife ; 

 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. — Leach. 



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. 



1. Adna sulcata. — The Furrowed Adna, pi. XCVII. f. 59. 



Wood pyrgoma. 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 



