A Study of Palaeozoic Arachnida, 第 37 卷

abdomen abdominal segments abdominal tergites anal operculum Anthracomarti Anthracosiro appendages Arachnida Architarbi belong British Museum carapace Carboniferous cephalothorax characters chelicerae cheliceral coxae Coal Measures convex Coseley crest Curculioides dorsal surface Eophrynus Eoscorpius Eurypterida eye-tubercle eyes Family femur fossil Arachnida fourth pair Fritsch front genera genital opening Genus Graeophonus Haptopoda Illinois intersegmental line juncture Karsch latter lungs marginal fields Mazon Creek Median tergal area metatarsus mouth movable Ninth tergite operculum Opiliones Order pair of coxae pair of legs Palaeophonus Palaeozoic Palpigradi paratype patella pedal coxae pedipalpal coxae Petrunkevitch Phrynichida Piece a shows Pocock Pocock's paratype posterior edge preserved Pruvost pygidium Recent represented Ricinulei Schizomida scorpions Scudder second sternite shape shown in Figure shows the dorsal shows the ventral sides somite species spiders spiracles sternite sternum structure Subclass tarsus tergal plate tergite Text-figures Thelyphonida tibia Total length transverse trend triangular Trigonotarbus tubercles ventral surface visible wider than long Xiphosura