"Diagrammatic cross-section of Cray-fish in the thoracic region, to show relation of circulation and respiration. a, appendage; c, carapace; c.f., flap of carapace overhanging the gills; d, digestive tube; g, gill; h, heart; l, liver; m, body muscles; m', muscles of the appendages; n.c., nerve cord; p.s., paricardial sinus; r, reproductive glands; st, sternal artery; v.a., ventral artery; v.s., ventral blood sinus in which the nerve cord lies." — Galloway

Cray-fish

"Diagrammatic cross-section of Cray-fish in the thoracic region, to show relation of circulation and…

"Eurypterus Fischeri, Eichwald. Silurian of Rootzikil. Restoration after Schmidt. The dorsal aspect is presented showing the prosomatic shield with paired compound eyes and the prosomatic appendages II. to IV. The small first pair of appendages is concealed from view by the carapace. 1 to 12 are the somites of the opisthosoma; 13, the post-anal spine." — The Encyclopedia Britannica, 1910

Eurypterus Fischeri

"Eurypterus Fischeri, Eichwald. Silurian of Rootzikil. Restoration after Schmidt. The dorsal aspect…

"Section through an early embryo of Limulus longispina, showing seven transverse divisions in the region of the unsegmented anterior carapace. The seventh, VII, is anterior to the genital operculum, op, and is the cavity of the praegenital somite which is more or less completely suppressed in subsequent development." — The Encyclopedia Britannica, 1910

Limulus Longispina

"Section through an early embryo of Limulus longispina, showing seven transverse divisions in the region…

"Ventral view of Limulus polyphemus. 1 to 6, The six prosomatic pairs of appendages. abd, the solid opisthosomatic carapace. tels, the post-anal spine (not the telson as the lettering would seem to imply, but only its post-anal portion). operc, the fused first pair of mesosomatic appendages forming the genital operculum." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"Ventral view of Limulus polyphemus. 1 to 6, The six prosomatic pairs of appendages. abd, the solid…

"Five stages in the development of the trilobite Sao hirsuta. A, Youngest stage. B, Older stage with distinct pygidial carapace. C, Stage with two free mesosomatic somites between the prosomatic and telsonic carapaces. D, Stage with seven free intermediate somites. E, Stage with twelve free somites; the telsonic carapace has not increased in size. a, Lateral eye. g, So-called facial "suture" (not really a suture). p, Telsonic carapace." — The Encyclopedia Britannica, 1910

Sao Hirsuto

"Five stages in the development of the trilobite Sao hirsuta. A, Youngest stage. B, Older stage with…

"Schizomus crassicaudatus, a Tartarid Pedipalp. Dorsal view of a male with the appendages cut short. I to VI. The prosomatic appendages. a, Anterior plate. b, Posterior plate of the prosomatic carapace. prae-gen, Tergum of the praegenital somite. II, The eleventh somite of the opisthosoma. pa, Post-anal lobe of the male—a conical body with narrow basal stalk." — The Encyclopedia Britannica, 1910

Schizomus

"Schizomus crassicaudatus, a Tartarid Pedipalp. Dorsal view of a male with the appendages cut short.…

"Diagram of a lateral view of a longitudinal section of a scorpion. d, Chelicera. ch, Chela. cam, Camerostome. m, Mouth. ent, Entosternum. p, Pecten. stig1, First pulmonary aperture. stig4, Fourth pulmonary aperture. dam, Muscle from carapace to a praeoral entosclerite. ad, Muscle from carapace to entosternum. md, Muscle from tergite of genital somite to entosternum. dv1 to dv6, Dorso-ventral muscles. pv1 to pv7, The seven veno-pericardiac muscles of the right side." — The Encyclopedia Britannica, 1910

Scorpion

"Diagram of a lateral view of a longitudinal section of a scorpion. d, Chelicera. ch, Chela. cam, Camerostome.…