A Monograph on the Sub-class Cirripedia · Charles Darwin
PLATE 18.
_Genus_--CHTHAMALUS. Fig. 1 _a_, Chthamalus stellatus, shell, _var. a_ (communis). 1 _b_, " " " " _e_ (depressus). 1 _c_, " " " " _c_ (communis). 1 _d_, " " " " _d_ (fragilis). 1 _e_, " " scutum and tergum, viewed inside, _var. c_, British. 1 _f_, " " scutum and tergum, viewed inside, _var. a_, Madeira. 1 _g_, " " scutum and tergum, viewed inside, _var. e_, Mediterranean. 1 _h_, " " scutum and tergum, viewed inside, _var. c_ and _e_, St. Jago, Cape de Verde Arch. 2, Chthamalus antennatus, shell. 3 _a_, Chthamalus dentatus, shell; 3 _b_, _var._ shell, attached to a ship's bottom; 3 _c_, tergum, viewed from within. 4 _a_, Chthamalus cirratus, scutum, viewed on inside; 4 _b_, tergum, viewed on inside. 5 _a_, Chthamalus Hembeli, shell, old specimen. 5 _b_, Chthamalus Hembeli, younger shell; C, carino-lateral compartment; _a′_, ala; _d_, radius; E, carina; _a′_, the two alæ. 5 _c_, Chthamalus Hembeli, scutum, external view of; 5 _d_, tergum, external view of; _e_, two of the crests, to which the tergal depressor muscles are attached, much enlarged and viewed from vertically beneath, showing the lateral denticuli or sub-crests. 6 _a_, Chthamalus fissus, shell; 6 _b_, scutum and tergum, separated, internal views of.
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