_Genus_--BALANUS.
Fig. 1 _a_, Balanus improvisus; 1 _b_, scutum, internal; 1 _c_,
tergum, external view.
2 _a_, Balanus nubilus, scutum, internal view; 2 _b_, tergum,
ditto; 2 _c_, tergum, external view.
3 _a_, 3 _b_, Balanus corrugatus, scutum and tergum, internal
view.
4 _a_, Balanus porcatus; 4 _b_ and 4 _c_, scutum and tergum,
internal views; 4 _d_, tergum external; 4 _e_, basal edge
of the parietes of wall of shell.
5 _a_, Balanus patellaris; 5 _b_, scutum, internal; 5 _c_,
tergum, external.
6 _a_, Balanus crenatus.
6 _b_, " " smooth _var._
6 _c_, " " elongated _var._
6 _d_ and 6 _e_, " scutum and tergum, external views.
6 _f_ and 6 _g_, " " " internal views.