ABSTRACT

Fig. 1 a, Balanus tintinnabulum, nat. size; small specimen ib, Balanus tintinnabulum, rostrum, internal view of, large speci­

men, nat. size lc, id, Balanus tintinnabulum, scutum and tergum, internal views

of, from recent specimens, the opercular valves not having been found fossil

Fig. 2a, Balanus calceolus, engraved from a recent specimen, the single fossil having been injured during examination

2b, 2c, Balanus calceolus, scutum and tergum, internal views 2d, Spur of tergum, variety: all from recent specimens, the

opercular valves not having been found fossil Fig. 3 a, 3 b, Balanus spongicola, scutum and tergum, external views

3c, 3 d, Balanus spongicola, scutum and tergum, internal views 3¿, Balanus spongicola, shell, enlarged from a recent specimen, the

single fossil being young, and having been injured by examina­ tion

Fig. 4a, Balanus concavus, shell (coralline crag specimen) 4b, Balanus concavus, internal view o f part of the carina (to the left

hand), of the carino-lateral compartment, and of part of the lateral compartment, showing the raised borders (r) on the rostral sides of the sutures in the sheath (Italian tertiary specimen)

4c, Balanus concavus, shell, var, with longitudinal ridges or ribs not prominent (coralline crag)

4d, Balanus concavus, smooth var. (Piedmont specimen) 4e, Balanus concavus, scutum, external view (coralline crag) 4f, Balanus concavus, scutum, internal view (coralline crag) 4g, Balanus concavus, tergum, external view (coralline crag) 4A, Balanus concavus, scutum, internal view (Maryland, U.S.)

recent) 4?n, Balanus concavus, tergum, external view (Portugal fossil, and

recent) 4w, Balanus concavus, scutum, internal view (Portugal fossil, and

recent) 40, Balanus concavus, tergum, external view, very large specimen

(Turin) 4/?, Balanus concavus, scutum, small portion, at the rostral corner,

highly magnified, very large specimen (Turin) Fig. 5a, Balanus porcatus, shell, nat. size (red crag) /

56, Balanus porcatus, small portion of basal margin of wall, much enlarged

5c, Balanus porcatus, portion of basal plate, much enlarged 5^, 5¿, 5/*, 5g, Balanus porcatus, scutum and tergum, external and

internal views; engraved from recent specimens, the opercular valves not having been positively found fossil

Fig. 6a, Balanus crenatus, twice nat. size (red crag) 6b, Balanus crenatus, small portion of basal margin of wall, much

enlarged 6c, Balanus crenatus, portion of basal plate, of unusual thickness,

much enlarged 6d, 6e, Balanus crenatus, scutum and tergum, external views from

recent specimens 6/, 6g, Balanus crenatus, scutum and tergum var., internal views

from recent specimens Figs 7a, 7 b, Balanus Hameri, scutum and tergum, external views

engraved from Canada glacial specimens, the opercular valves not having been found in Great Britain

7c, 7d, Balanus Hameri, scutum and tergum, internal views of very large and old specimens (Canada and Uddevalla) /