A Monograph on the Sub-class Cirripedia · Charles Darwin
PLATE 4.
_Genus_--BALANUS. Fig. 1 _a_ and 1 _b_, Balanus spongicola, external views of scutum and tergum; 1 _c_, _var._ of the tergum, from a specimen from the Cape of Good Hope; 1 _d_, _var._ of the tergum from the West Indies. 2, Balanus lævis. 2 _a_, " " fossil, elongated _var._, showing lower part of basal cup filled up with a cancellated mass. 2 _b_ and 2 _c_, " " scutum, external and internal view of. 2 _d_ and 2 _e_, " " scutum (_variety_), internal and external view of. 2 _f_, " " scutum (_variety_), external view. 2 _g_, " " tergum, external view. 3 _a_, Balanus perforatus, scutum, internal view; 3 _b_, tergum, internal view; 3 _c_, tergum, _var._ external view. 4 _a_, Balanus concavus (_var._ from Panama), scutum, internal view; 4 _b_, scutum, external view; 4 _c_, tergum, external view; 4 _d_, tergum, fossil, Coralline Crag; 4 _e_, tergum, fossil, Italy.
Text from Project Gutenberg, public domain in the United States.