A Monograph on the Sub-class Cirripedia · Charles Darwin
PLATE 9.
_Sub-Genus_--ACASTA. Fig. 1 _a_, Acasta spongites; 1 _b_, scutum, external view; 1 _c_, scutum, internal; 1 _d_, tergum, internal. 2 _a_, Acasta sulcata; 2 _b_, _var._, lateral compartment of; 2 _c_ and 2 _d_, terga, internal views of two varieties. 3 _a_, Acasta cyathus; 3 _b_ and 3 _c_, scutum and tergum, internal views. 4, Acasta undulata, scutum, external view. 5 _a_, Acasta glans, basis seen from within; 5 _b_, compartments of a smaller specimen, seen from within; carina on the right-hand, cut into two; carino-lateral and lateral compartments to the left-hand; 5 _c_, tergum, internal view. 6 _a_, Acasta lævigata, tergum, internal view; 6 _b_, another _var._ 7 _a_, Acasta fenestrata; 7 _b_, scutum, and 7 _c_, tergum, internal views. 8 _a_, Acasta purpurata; 8 _b_, scutum; 8 _c_, tergum, internal views. 9 _a_, Acasta sporillus; 9 _b_, carino-lateral compartment (almost rudimentary) and lateral compartment, seen from within; 9 _c_ and 9 _d_, scutum and tergum, seen from within.
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