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"Diagram of the arterial system of A, Scorpio, and B, Limulus. The Roman numerals indicate the body somites and the two figures are adjusted for comparison. ce, Cerebral arteries; sp, supra-spinal or medullary artery; c, caudal artery; l, lateral anastomotic artery of Limulus. The figure B also shows the peculiar neural investiture formed by the cerebral arteries in Limulus and the derivation from this of the arteries to the limbs, III, IV, VI, whereas in Scorpio the latter have a seperate origin from the anterior aorta." — The Encyclopedia Britannica, 1910

Arterial System

"Diagram of the arterial system of A, Scorpio, and B, Limulus. The Roman numerals indicate the body…

"Ventral surface of the entosternum of Limulus polyphemus, Latr. NF, neural fossa protecting the aggregated ganglia of the central nervous system; PVP, left posterior ventral process; PMP, posterior median process. Natural size." — The Encyclopedia Britannica, 1910

Limulus

"Ventral surface of the entosternum of Limulus polyphemus, Latr. NF, neural fossa protecting the aggregated…

"The remaining three pairs of mesosomatic appendages of Scorpio and Limulus. l130 indicates that there are 130 lamellae in the scorpion's lung-book, whilst l150 indicates that 150 similar lamellae are counted in the gill of Limulus." — The Encyclopedia Britannica, 1910

Limulus

"The remaining three pairs of mesosomatic appendages of Scorpio and Limulus. l130 indicates that there…

"Section through a portion of the lateral eye of Limulus, showing three ommatidia—A, B and C. hyp, The epidermic cell-layer (so-called hypodermis), the cells of which increase in volume below each lens, l, and become nerve-end cells or retinula-cells, rl; in A, the letters rh point to a rhabdomere secreted by the cell rl; c, the peculiar central spherical cell; n, nerve fibers; mes, mesoblastic skeletal tissue; ch, chitinous cuticle." — The Encyclopedia Britannica, 1910

Limulus

"Section through a portion of the lateral eye of Limulus, showing three ommatidia—A, B and C.…

"Section through one of the central eyes of a young Limulus. L, Cuticular or corneous lens. hy, Epidermic cell-layer. corn, Its corneagen portion immediately underlying the lens. ret, Retinula cells. nf, Nerve fibers. con. tiss, Connective tissue (mesoblastic skeletal tissue)." — The Encyclopedia Britannica, 1910

Limulus

"Section through one of the central eyes of a young Limulus. L, Cuticular or corneous lens. hy, Epidermic…

"Transverse section of a retinula of the lateral eye of Limulus, showing ten retinula cells (ret), each bearing a rhabdomere (rhab)." — The Encyclopedia Britannica, 1910

Limulus

"Transverse section of a retinula of the lateral eye of Limulus, showing ten retinula cells (ret), each…

"Diagram of a lateral view of a longitudinal section of Limulus. Suc, Suctorial pharynx. al, Alimentary canal. Ph, Pharynx. M, Mouth. Est, Entosternum. VS, Ventral venous sinus. chi, Chilaria. go, Genital operculum. br1 to br5, Branchial appendages. met, Unsegmented metasoma. Entap4, Fourth dorsal entapophysis of left side. tsm, Tergo-sternal muscles, six pairs as in Scorpio. VPM1 to VPM8, The eight pairs of veno-pericardiac muscles." — The Encyclopedia Britannica, 1910

Limulus

"Diagram of a lateral view of a longitudinal section of Limulus. Suc, Suctorial pharynx. al, Alimentary…

"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…

"Diagram of the dorsal surface of Limulus polyphemus. oc, Lateral compound eyes. oc', Central monomeniscous eyes. PA, Post-anal spine. I to VI, The six appendage-bearing somites of the prosoma. VII, Usually considered to be the tergum of the genital somite, but suggested by Pocock to be that of the otherwise suppressed praegenital somite. VIII to XIII, The six somites of the mesosoma, each with a movable pleural spine and a pair of dorsal entopophysis or muscle-attaching ingrowths. XIV to XVIII, The confluent or unexpressed six somites of the metasoma." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"Diagram of the dorsal surface of Limulus polyphemus. oc, Lateral compound eyes. oc', Central monomeniscous…

"Ventral view of the posterior carapace or meso-metasomatic (opisthosomatic) fusion of Limulus polyphemus. The soft integument and limbs of the mesosoma have been removed as well as all the viscera and muscles, so that the inner surface of the terga of these somites with their entopophyses are seen. The unsegmented dense chitinous sternal plate of the metasoma (XIII to XVIII) is not removed." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"Ventral view of the posterior carapace or meso-metasomatic (opisthosomatic) fusion of Limulus polyphemus.…

"Third leg of Limulus polyphemus, showing the division of the fourth segment of the leg by a groove S into two, thus giving seven segments to the leg as in scorpion." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"Third leg of Limulus polyphemus, showing the division of the fourth segment of the leg by a groove…

"View of the ventral surface of the mid-line of the prosomatic region of Limulus polyphemus. The coxae of the five pairs of limbs following the chelicerae were arranged in a series on each side between the mouth, M, and the metasternites, mets. sf, The sub-frontal median sclerite. Ch, the chelicerae. cam, The camerostome or upper lip. M, the mouth. pmst, The promesosternal sclerite or chitinous plate, unpaired. mets, the right and left metasternites (corresponding to the similarly placed pentagonal sternite of Scorpio." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"View of the ventral surface of the mid-line of the prosomatic region of Limulus polyphemus. The coxae…

"The right coxal gland of Limulus polyphemus, Latr. a2 to a5, Posterior borders of the chitinous bases of the coxae of the second, third, fourth and fifth prosomatic limbs. b, Longitudinal lobe or stolon of the coxal gland. c, It's four transverse lobes or outgrowths corresponding to the four coxae." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"The right coxal gland of Limulus polyphemus, Latr. a2 to a5, Posterior borders of the chitinous bases…

"So-called "trilobite stage" of Limulus polyphemus. A, Dorsal; B, ventral view." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"So-called "trilobite stage" of Limulus polyphemus. A, Dorsal; B, ventral view." — The Encyclopedia…

"Dorsal view of Limulus polyphemus, Latr." — The Encyclopedia Britannica, 1910

Limulus Polyphemus

"Dorsal view of Limulus polyphemus, Latr." — The Encyclopedia Britannica, 1910

"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…

"The first three pairs of mesosomatic appendages of Scorpio and Limulus compared. VII. The genital operculum; VIII. The pectens of Scorpio and the first branchial plate of Limulus; IX. The first pair of lung-books of Scorpio and the second branchial plate of Limulus. gp, Genital pore; epst, Epistigmatic sclerite; stg, Stigma or orifice of the hollow tendons of the branchial plates of Limulus." — The Encyclopedia Britannica, 1910

Mesosomatic

"The first three pairs of mesosomatic appendages of Scorpio and Limulus compared. VII. The genital operculum;…

"Comparison of the sixth prosomatic limb of a recent scorpion (B), of Palaeophonus (C), and of Limulus (A), showing their agreement in the number of segments; in the existence of a movable spine, Sp, at the distal border of the fifth segment; in the correspondence of the two claws at the free end of the limb of Scorpio with two spines similarly placed in Limulus; and, lastly, in the correspondence of the three talon-like spines carried on the distal margin of segment six of recent scorpions with the four larger but similarly situated spines of the leg of Limulus; s, groove dividing the ankylosed segments 4 and 5 of the Limulus leg into two." — The Encyclopedia Britannica, 1910

Prosomatic Limb

"Comparison of the sixth prosomatic limb of a recent scorpion (B), of Palaeophonus (C), and of Limulus…