Fig. 
Fig. 
Fig. 
TAB. IL. 
. la, Balanus Hameri, lateral compartment, viewed externally. 
14, x $ carino-lateral compartment, viewed internally. 
. 2a, Balanus bisulcatus, shell, 14 nat. size. 
26, 5s ‘: rostrum, viewed externally, to show the commencement of 
the folding of the walls, 1} nat. size. 
2c, A a var. plicatus, thrice nat. size. 
2d, 2 . very young shell, probably belonging to this species, enlarged 
about seven times. 
ZOsap, 53 - scutum and tergum, external views. 
29, 2h 5; _ . - internal views. 
3a, Balanus dolosus, rostrum, much enlarged, viewed internally. 
36, x . portion of basal plate, much enlarged. 
OG, ob. »  scutum and tergum, external views. 
4a, Balanus unguiformis, shell, twice nat. size. 
Ab, ES > shell, var. erisma, twice nat. size. 
Ac, 4d, ,, _ scutum and tergum, external views. 
Ae, Af, ,, x rd 7. internal views. 
5a, Balanus inclusus, shell, nearly thrice nat. size. 
5d, e . basis of ditto, showing basal edges of the compartments. 
Be, a dr var., with its rostro-carinal axis elongated. 
5d, Cb ” var; " br 2B showing the narrow 
furrowed basis and lower portions of the six compartments. 
De, hs - var. wtermediate between the last two varieties, basal view of, 
nearly twice nat. size. 
of, 59; 5, ‘, scutum and tergum, internal views from a very young 
specimen. 
g. 6a, Acasta undulata, rostrum viewed externally ; spinose var. ; twice nat. size. 
Obi Sr 54 lateral compartment, smooth var., twice nat. size. 
Gem a -. oy basal cup. 
Ojam =e vy scutum viewed internally. 
6e, 6f,, 3 , and tergum viewed externally. 
g. 7a, Pyrgoma Anglicum, shell, viewed from above, four times nat. size. 
74, Ps Y scutum, internal view. 
Te, - 3 tergum, internal view, engraved from recent specimen, this 
valve not having been found fossil, 
