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"Diagram to show the way in which an outgrowing gill-process bearing blood-holding lamellae, may give rise, if the sternal body wall sings inwards, to a lung-chamber with air-holding lamellae. I is the embryonic condition. L is the condition of outgrowth with gl, gill lamellae. A is the condition of insinging of the sternal surface and consequent enclosure of the lamelligerous surface of the appendage in a chamber with narrow orifice—the pulmonary air-holding chamber. pl, Pulmonary lamellae. bs, Blood sinus." — The Encyclopedia Britannica, 1910

Lamellae

"Diagram to show the way in which an outgrowing gill-process bearing blood-holding lamellae, may give…

"Diagrams of the meta-sternite st, with genital operculum op, and the first lamelligerous pair of appendages ga, with uniting sternal element st of Scorpio (left) and Limulus (right)." — The Encyclopedia Britannica, 1910

Meta-sternite

"Diagrams of the meta-sternite st, with genital operculum op, and the first lamelligerous pair of appendages…

"Embryo of scorpion, ventral view showing somites and appendages. sgc, Frontal groove. sa, Rudiment of lateral eyes. obl, Camerostome (upper lip). so, Sense-organ of Patten. PrGabp1, Rudiment of the appendage of the praegenital somite which disappears. abp2, Rudiment of the right half of the genital operculum. abp3, Rudiment of the right half of the genital operculum. abp4 to abp7, Rudiments of the four appendages which carry the pulmonary lamellae. I to VI, Rudiments of the six limbs of the prosoma. VIIPrG, The evanescent praegenital somite. VIII, The first mesosomatic somite or genital somite. IX, The second mesosomatic somite or pectiniferous somite. X to XIII, The four pulmoniferous somites. XIV, The first metasomatic somite." — The Encyclopedia Britannica, 1910

Scorpio Embryo

"Embryo of scorpion, ventral view showing somites and appendages. sgc, Frontal groove. sa, Rudiment…