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Functional morphology of the prosoma of Baltoeurypterus tetragonophthalmus (Fischer) (Chelicerata: Eurypterida)

Published online by Cambridge University Press:  03 November 2011

Paul A. Selden
Paul A. Selden
Affiliation:
Department of Extra-Mural Studies, University of Manchester, Manchester M13 9PL, England
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Abstract

The prosomal morphology of Baltoeurypterus tetragonophthalmus (Fischer) from the Baltic Silurian is redescribed and reconstructed. The first eurypterid labrum and new secondary sexual characters of Baltoeurypterus are described. The radially-arranged coxae of Baltoeurypterus were capable of adduction and abduction for food mastication, but not promotor-remotor movements for locomotion. Joint diagrams are presented for the first time for an extinct arthropod. Promotion and remotion of the limbs occurred about subvertical trochanteral pivots, as in all other chelicerates except xiphosurans. Baltoeurypterus probably walked in a “slow” gait; a method of choosing possible gaits for extinct arthropods is outlined. Swimming in Baltoeurypterus was effected by means of a rowing action of the posterior limb pair, which is provided with complex joints for collapsing the paddle during the recovery stroke. The limb arrangement and joint mechanisms of Baltoeurypterus are intermediate between those of the xiphosurans and the arachnids. It is possible that a sister relationship exists between the eurypterids and some arachnid groups, which would render Merostomata and Arachnida unnatural assemblages.

Keywords

ArthropodaEstoniaFeedingGotlandLocomotionMerostomataSilurianSwimmingWalking
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 72 , Issue 1 , 1981 , pp. 9 - 48
Copyright
Copyright © Royal Society of Edinburgh 1981

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References

Andrews, H. E., Brower, J. C, Gould, S. J. & Reyment, R. A. 1974. Growth and variation in Eurypterus remipes DeKay. BULL GEOL INST UNIV UPSALA 4, 81–114.Google Scholar
Barber, S. B. 1956. Chemoreception and proprioception in Limulus. J EXP ZOOL 131, 51–74.CrossRefGoogle Scholar
Barbour, E. H. 1914. Carboniferous eurypterids of Nebraska. AM J SCI 38, 507–10.CrossRefGoogle Scholar
Barr, D. & Smith, B. P. 1979. The contribution of setal blades to effective swimming in the aquatic mite Limnochares americana (Acari: Prostigmata: Limnocharidae). ZOOL J LINN SOC 65, 55–69.CrossRefGoogle Scholar
Briggs, D. E. G., Rolfe, W. D. I. & Brannan, J. 1979. A giant myriapod trail from the Namurian of Arran, Scotland. PALAEONTOLOGY 22, 273–91.Google Scholar
Bristowe, W. S. 1958. The World of Spiders. London: Collins. Bruton D. L. 1981. The Middle Cambrian arthropod Sidneyia, Burgess Shale, British Columbia. PHILOS TRANS R SOC LONDON B, in press.Google Scholar
Clark, B. D. & Bemis, W. 1979. Kinematics of swimming of penguins at the Detroit Zoo. J ZOOL LONDON 188, 411–28.CrossRefGoogle Scholar
Clarke, J. M. & Ruedemann, R. 1912. The Eurypterida of New York. MEM NEW YORK STATE MUS NAT HIST 14, vol. I pp. 1–439, vol. II plates.Google Scholar
Clarkson, E. N. K. 1975. The evolution of the eye in trilobites. FOSSILS AND STRATA 4, 7–31.CrossRefGoogle Scholar
Couzijn, H. W. C. 1976. Functional anatomy of the walking-legs of Scorpionida with remarks on terminology and homologization of leg segments. NETH J ZOOL 26, 453–501.CrossRefGoogle Scholar
Dalingwater, J. E. 1973. The cuticle of a eurypterid. LETHAIA 6, 179–86.CrossRefGoogle Scholar
Dalingwater, J. E. 1975. Further observations on eurypterid cuticles. FOSSILS AND STRATA 4, 271–9.CrossRefGoogle Scholar
Dalingwater, J. E. 1980. SEM observations on the cuticles of some chelicerates. 8th INT ARACHNOL CONGR VIENNA 1980, 285–9.Google Scholar
DeKay, J. E. 1825. Observations on a fossil crustaceous animal of the order Branchiopoda. ANN LYCEUM NAT HIST 1, 375–7.Google Scholar
Dennell, R. 1960. Integument and exoskeleton. In Waterman, T. H. (ed.) The Physiology of Crustacea, vol. 1, 449–72. New York: Academic Press.Google Scholar
Depitout, A. 1962. Etude des gigantostraces siluriens du Sahara central. PUBL CENT RECH SAHARIENNES GEOL 2, 1–141.Google Scholar
Edel, R. K. & Winn, H. E. 1978. Observations on underwater locomotion and flipper movement of the humpback whale Megaptera novaeangliae. MAR BIOL BERLIN 48, 279–87.CrossRefGoogle Scholar
Eichwald, E. von 1854. Die Grauwackenschichten von Liev- und Esthland. BULL SOC NAT MOSCOU 27, 3–111.Google Scholar
Eichwald, E. von 1860. Lethaea Rossica, vol. 1. Stuttgart: Schweizerbart.Google Scholar
Eisenack, A. 1956. Beobachtungen an Fragmenten von Eurypteriden-Panzern. NEUES JAHRB GEOL PALAEONTOL ABH 104, 119–28.Google Scholar
English, A. W. 1976. Limb movements and locomotor function in the California sea lion (Zalophus californianus). J ZOOL LONDON 178, 341–64.CrossRefGoogle Scholar
Evans, M. E. G. 1977. Locomotion in the Coleoptera Adephaga, especially Carabidae. J ZOOL LONDON 181, 189–226.CrossRefGoogle Scholar
Firstman, B. 1973. The relationship of the chelicerate arterial system to the evolution of the endosternite. J ARACHNOL 1, 1–54.Google Scholar
Fischer de Waldheim, G. 1839. Notice sur un crustace fossile du genre Eurypterus de Podolie. BULL SOC NAT MOSCOU 11, 125–8.Google Scholar
Fisher, D. C. 1975. Swimming and burrowing in Limulus and Mesolimulus. FOSSILS AND STRATA 4, 281–90.CrossRefGoogle Scholar
Fisher, D. C. 1979. Evidence for subaerial activity of Euproops danae (Merostomata, Xiphosurida). In Nitecki, M. H. (ed.) Mazon Creek Fossils, 379–447. New York: Academic Press.CrossRefGoogle Scholar
Fortey, R. A. & Clarkson, E. N. K. 1976. The function of the glabellar ‘tubercle’ in Nileus and other trilobites. LETHAIA 9, 101–6.CrossRefGoogle Scholar
Gnatzy, W. & Tautz, J. 1977. Sensitivity of an insect mechanoreceptor during moulting. PHYSIOL ENTOMOL 2, 279–88.CrossRefGoogle Scholar
Gray, J. 1968. Animal Locomotion. London: Weidenfeld & Nicholson.Google Scholar
Hall, J. 1859. Palaeontology of New York, Vol. 3 (In Natural History of New York Part 4) part 1, 382–419; part 2, plates 80–84A. Albany: New York State Museum.Google Scholar
Hammen, L. van der 1977. A new classification of Chelicerata. ZOOL MEDED LEIDEN 51, 307–19.Google Scholar
Hammen, L. van der 1979. Comparative studies on Chelicerata I. The Cryptognomae (Ricinulei, Architarbi and Anactinotrichida). ZOOL VERH 174, 1–62.Google Scholar
Hanken, N.-M. & Stø;rmer, L. 1975. The trail of a large Silurian eurypterid. FOSSILS AND STRATA 4, 255–70.CrossRefGoogle Scholar
Hansen, H. J. 1925. Studies on Arthropoda II. On the Comparative Morphology of the Appendages in the Arthropoda. A. Crustacea. Copenhagen: Gyldendalske Boghandel.Google Scholar
Hansen, H. J. 1930. Studies on the Arthropoda III. On the Comparative Morphology of the Appendages in the Arthropoda. B. Crustacea (Supplement), Insecta, Myriapoda and Arachnida. Copenhagen: Gyldendalske Boghandel.Google Scholar
Hartnoll, R. G. 1971. The occurrence and significance of swimming in the Brachyura. ANIM BEHAV 19, 34–50.CrossRefGoogle Scholar
Haupt, i. & Coineau, Y. 1978. Moulting and morphogenesis of sensilla in a prostigmatic mite (Acari, Actinotrichida, Actinedida: Caeculidae). 1. Mechanoreceptive bristles. CELL TISSUE RES 186, 63–79.CrossRefGoogle Scholar
Hede, J. E. 1929. Berggrunden (Silursystemet). In Munthe, H., Hede, J. E. & Lundqvist, G.Beskrivning till kartbladet Katthammarsvik. SVER GEOL UNDERS ser. Aa 170, 14–57.Google Scholar
Holm, G. 1896. Uber eine neue Bearbeitung des Eurypterus fischeri Eichw. BULL ACAD SCI ST PETERSBOURG 4, 369–72.Google Scholar
Holiti, G. 1898. Uber die Organisation des Eurypterus fischeri Eichw. MEM ACAD SCI ST PETERSBOURG 8, 1–57.Google Scholar
Holm, G. 1899. Palaeontologiska notiser: 13. Om den yttre anatomien hos Eurypterus fischeri. GEOL FOEREN STOCKHOLM FOERH 21, 83–128.CrossRefGoogle Scholar
Hoyle, G. 1976. Arthropod walking. In Herman, R. M., Grillner, S., Stein, P. S. G. & Stuart, D. G. (eds) Neural Control of Locomotion. ADV BEHAV BIOL 18, 137–79, New York: Plenum Press.Google Scholar
Hughes, C. P. 1975. Redescription of Burgessia bella from the Middle Cambrian Burgess Shale, British Columbia. FOSSILS AND STRATA 4, 415–35.CrossRefGoogle Scholar
Hughes, G. M. 1958. The co-ordination of insect movements. III. Swimming in Dytiscus, Hydrophilus, and a dragonfly nymph. J EXP BIOL 35, 567–83.CrossRefGoogle Scholar
Hughes, G. M. & Mill, P. J. 1974. Locomotion: terrestrial. In Rockstein, M. (ed.) The Physiology of Insecta, 2nd edn, vol. III, 335–79. New York: Academic Press.CrossRefGoogle Scholar
Kaestner, A. 1968. Invertebrate Zoology II – Arthropod relatives, Chelicerala, Myriapoda (translated and adapted from the German by Levi, H. W. & Levi, L. R.) 2nd edn.New York: Interscience.Google Scholar
Kaljo, D. 1970. Silur Estonii. Tallin: Institut Geologii Akademii Nauk Estonickoi CCP.Google Scholar
Kennedy, T. S. 1945. Observations on the mass migration of desert locust hoppers. TRANS R ENTOMOL SOC LONDON 95, 247–62.CrossRefGoogle Scholar
Kjellesvig-Waering, E. N. 1979. Eurypterids. In Jaanusson, V., Laufeld, S. & Skoglund, R. (eds). Lower Wenlock faunal and floral dynamics – Vattenfallet section, Gotland. SVER GEOL UNDERS AFH C 762, 57–64.Google Scholar
Kiihl, H. 1933. Die Fortbewegung der Schwimmkrabben mit Bezug auf die Plastizitat des Nervensystems. Z VGL PHYSIOL 19, 489–521.CrossRefGoogle Scholar
Lankester, E. R., Benham, W. B. S. & Beck, E. J. 1885. On the muscular and endoskeletal systems of Limulus and Scorpio; with some notes on the anatomy and generic characters of scorpions. TRANS ZOOL SOC LONDON 11, 311–84.CrossRefGoogle Scholar
Lauck, D. R. 1959. Locomotion of Lethocerus (Hemiptera: Belostomatidae). ANN ENTOMOL SOC AM 52, 93–9.CrossRefGoogle Scholar
Laurie, M. 1893. The anatomy and relations of the Eurypteridae. TRANS R SOC EDINBURGH 37, 509–28.CrossRefGoogle Scholar
Levi-Setti, R. 1975. Trilobites: A Photographic Atlas. Chicago: University of Chicago Press.Google Scholar
Lochhead, J. H. 1961. Locomotion. In Waterman, T. H. (ed.) The Physiology of Crustacea, vol. II, 313–64. New York: Academic Press.Google Scholar
Manten, A. A. 1971. Silurian Reefs of Gotland. Developments in Sedimentology 13. Amsterdam: Elsevier.Google Scholar
Manton, S. M. 1952. The evolution of arthropodan locomotory mechanisms. Part 2. General introduction to the locomotory mechanisms of the Arthropoda. J LINN SOC (ZOOL) 42, 93–117.CrossRefGoogle Scholar
Manton, S. M. 1958. Hydrostatic pressure and leg extension in arthropods, with special reference to arachnids. ANN MAG NAT HIST 1, 161–82.CrossRefGoogle Scholar
Manton, S. M. 1964. Mandibular mechanisms and the evolution of arthropods. PHILOS TRANS R SOC LONDON B 247, 1–183.Google Scholar
Manton, S. M. 1965. The evolution of arthropodan locomotory mechanisms. Part 8. Functional requirements and body design in Chilopoda, together with a comparative account of their skeleto-muscular systems and an appendix on a comparison between burrowing forces of annelids and chilopods and its bearing upon the evolution of the arthropodan haemocoel. J LINN SOC (ZOOL) 45, 251–484.CrossRefGoogle Scholar
Manton, S. M. 1972. The evolution of arthropodan locomotory mechanisms. Part 10. Locomotory habits, morphology and evolution of the hexapod classes. ZOOL J LINN SOC 51, 203–400.CrossRefGoogle Scholar
Manton, S. M. 1973a. Arthropod phylogeny – a modern synthesis. J ZOOL LONDON 171, 111–30.CrossRefGoogle Scholar
Manton, S. M. 1973b. The evolution of arthropodan locomotory mechanisms. Part 11. Habits, morphology and evolution of the Uniramia (Onychophora, Myriapoda, Hexapoda) and comparisons with the Arachnida, together with a functional review of uniramian musculature. ZOOL J LINN SOC 53, 257–375.Google Scholar
Manton, S. M. 1977. The Arthropoda: Habits, Functional Morphology, and Evolution. Oxford: Oxford University Press.Google Scholar
Miller, J. 1975. Structure and function of trilobite terrace lines. FOSSILS AND STRATA 4, 155–78.CrossRefGoogle Scholar
Miller, J. 1976. The sensory fields and life mode of Phacops rana (Green, 1832) (Trilobita). TRANS R SOC EDINBURGH 69, 337–67.Google Scholar
Miller, P. L. 1972. Swimming in mantids. J ENTOMOL LONDON 46, 91–7.Google Scholar
Milne, L. & Milne, M. 1967. The Crab that Crawled out of the Past. London: Bell.Google Scholar
Mitchill, S. L. 1818. An account of the impressions of a fish in the rocks of Oneida county, New York. AM MON MAG CRIT REV 3, 291.Google Scholar
Mutvei, H. 1977. SEM studies of arthropod exoskeletons. 2. Horseshoe crab Limulus polyphemus (L.) in comparison with extinct eurypterids and recent scorpions. ZOOL SCR 6, 203–13.CrossRefGoogle Scholar
Nachtigall, W. 1960. Uber Kinematik, Dynamik und Energetik des Schwimmens einheimischer Dytisciden. Z VGL PHYSIOL 43, 48–118.CrossRefGoogle Scholar
Nachtigall, W. 1962. Funktionelle Morphologie, Kinematik und Hydromechanik des Ruderapparates von Gyrinus. Z VGL PHYSIOL 45, 193–226.CrossRefGoogle Scholar
Nachtigall, W. 1974. Locomotion: mechanics and hydrodynamics of swimming in aquatic insects. In Rockstein, M. (ed.) The Physiology of Insecta, 2nd edn, vol. III, 382–432. New York: Academic Press.Google Scholar
Nieszkowski, J. 1858. De Euryptero Remipede. (dissertation). Dorpat: Glaser.Google Scholar
Nieszkowski, J. 1859. Der Eurypterus remipes aus den obersilurischen Schichten der Insel Oesel. ARCH NATURKD LIVEST-KURLANDS 2, 299–344.Google Scholar
Patten, W. 1894. On the morphology and physiology of the brain and sense organs of Limulus. Q J MICROSC SCI 35, 1–96.Google Scholar
Petrunkevitch, A. 1955. Arachnida. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology. P. Arthropoda 2, P42–P162. Lawrence, Kansas: University of Kansas & Geological Society of America.Google Scholar
Robinson, J. A. 1975. The locomotion of plesiosaurs. NEUES JAHRB GEOL PALAEONTOL ABH 149, 286–332.Google Scholar
Rosenheim, O. 1905. Chitin in the carapace of Pterygotus osiliensis, from the Silurian rocks of Oesel. PROC R SOC LONDON B 76, 398–400.Google Scholar
Savory, T. H. 1964. Arachnida. London: Academic Press.Google Scholar
Schenke, G. 1963. Untersuchungen zum Bau und zur Funktion der Schwimmenextremitaten von Corixa punctata Illig. ENTOMOL BER 1, 83–92.Google Scholar
Schenke, G. 1965a. Die Ruderbewegungen von Corixa punctata Illig. (Cryptocerata). INT REV GESTAMTEN HYDROBIOL 50, 73–84.CrossRefGoogle Scholar
Schenke, G. 1965b. Schwimmgeschwindigkeit, Schlagfrequenz und Steuern von Corixa punctata Illig. ZOOL ANZ 176, 5–12.Google Scholar
Schenke, G. 1965c. Zu einigen morphologischen Voraussetzungen des Schwimmens von Corixa punctata Illig. 1807 (Hemiptera, Heteroptera). WISS Z PAEDAGOG HOCHSCH POTSDAM 9, 399–408.Google Scholar
Schenke, G. 1965d. Schwimmhaarsystem und Rudern von Notonecta glauca. Z MORPHOL OEKOL TIERE 55, 631–40.CrossRefGoogle Scholar
Schmidt, F. 1883. Die Crustaceenfauna der Eurypterenschichten von Rootzikiill auf Oesel – Miscellanea silurica III. MEM ACAD SCI ST PETERSBOURG 31, 28–85.Google Scholar
Schrenk, A. 1854. Uebersicht des oberen silurischen Schichtensystems Liv- und Esthlands, vornahmlich ihrer Inselgruppe. ARCH NATURKD LIV- EST- KURLANDS 1, 1–112.Google Scholar
Shelton, R. G. J. & Laverack, M. S. 1968. Observations on a redescribed crustacean cuticular sense organ. COMP BIOCHEM PHYSIOL 25, 1049–59.CrossRefGoogle Scholar
Smith, B. P. & Barr, D. 1977. Swimming by the water mite Limnochares americana Lundblad (Acari, Parasitengona, Limnocharidae). CAN J ZOOL 55, 2050–9.CrossRefGoogle Scholar
Spirito, C. P. 1972. An analysis of the swimming behavior of the portunid crab Callinectes sapidus. MAR BEHAV PHYSIOL 1, 261–76.CrossRefGoogle Scholar
Stockton, W. L. & Cowen, R. 1976. Stereoscopic vision in one eye: paleophysiology of the schizochroal eye of trilobites. PALEOBIOLOGY 2, 304–15.CrossRefGoogle Scholar
Størmer, L. 1934. Merostomata from the Downtonian sandstone of Ringerike, Norway. SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1933 10, 1–125.Google Scholar
Størmer, L. 1936. Eurypteriden aus den Rheinischen Unterdevon. ABH PREUSS GEOL LANDESANST 175, 1–74.Google Scholar
Størmer, L. 1938. Ewypterus fischeri in Ludlow beds (9d) at Ringerike. NOR GEOL TIDSKR 18, 69–70.Google Scholar
Størmer, L. 1944. On the relationships and phytogeny of fossil and Recent Arachnomorpha. (A comparative study on Arachnida, Xiphosura, Eurypterida, Trilobita, and other fossil Arthropoda). SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1944 5, 1–158.Google Scholar
Størmer, L. 1955. Merostomata. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology. P. Arthropoda 2, P1–P41. Lawrence, Kansas: University of Kansas & Geological Society of America.Google Scholar
Størmer, L. 1963. Gigantoscorpio willsi, a new scorpion from the Lower Carboniferous of Scotland and its associated preying microorganisms. SKR NOR VIDENSK-AKAD MATNATURVIDENSK KL 1963 8, 1–171.Google Scholar
Størmer, L. 1972. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 2: Xiphosura. SENCKENBERGIANA LETHAEA 53, 1–29.Google Scholar
Størmer, L. 1973. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 3: Eurypterida, Hughmilleriidae. SENCKENBERGIANA LETHAEA 54,119–205.Google Scholar
Størmer, L. 1974. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 4: Eurypterida, Drepanopteridae, and other groups. SENCKENBERGIANA LETHAEA 54, 359–451.Google Scholar
Størmer, L. 1976. Arthropods from the Lower Devonian (Lower Emsian) of Alken an der Mosel, Germany. Part 5: Myriapoda and additional forms, with general remarks on fauna and problems regarding invasion of land by arthropods. SENCKENBERGIANA LETHAEA 57, 87–183.Google Scholar
Størmer, L. 1980. Sculpture and microstructure of the exoskeleton in chasmopinid and phacopid trilobites. PALAEONTOLOGY 23, 237–71.Google Scholar
Størmer, L. & Kjellesvig-Waering, E. N. 1969. Sexual dimorphism in eurypterids. In Westermann, G. E. G. (ed.) Sexual Dimorphism in Fossil Metazoa and Taxonomic Implications. International Union of Geological Sciences Ser. A, No. 1, 201–14. Stuttgart: Schweizerbart.Google Scholar
Tarasoff, F. J., Bisaillon, A., Pierard, J. & Whitt, A. P. 1972. Locomotory patterns and external morphology of the river otter, sea otter and harp seal. CAN J ZOOL 50, 915–31.CrossRefGoogle ScholarPubMed
Tobien, H. 1937. Uber Sinneshaare bei Pterygotus (Erettopterus) osiliensis Schmidt aus dem Obersilur von Oesel. PALAEONTOL Z 19, 254–66.CrossRefGoogle Scholar
Vachon, M. 1945. Remarques sur les appendices du prosoma des Limules at leur arthrogenese. ARCH ZOOL EXP GEN 84, 271–300.Google Scholar
Vascautanu, T. 1932. Formatiunile Siluriene din Malul Romanesc al Nistrului (Contributiuni al Cunoasterea Paleozoicului din Basinul Moldo-podolic). ANU INST GEOL ROM 15, 425–663.Google Scholar
Versluys, J. & Demoll, R. 1923. Das Limulus-Problem. Die Verwandtschaftsbeziehungen der Merostomen und Arachnoiden unter sich und mit anderen Arthropoden. ERGEB FORTSCHR ZOOL 5, 67–388.Google Scholar
Walker, W. F. 1971. Swimming in sea turtles of the family Cheloniidae. COPEIA 1971, 229–33.CrossRefGoogle Scholar
Ward, D. V. 1969. Leg extension in Limulus. BIOL BULL MAR BIOL LAB WOODS HOLE 136, 288–300.CrossRefGoogle Scholar
Warner, G. F. 1977. The Biology of Crabs. London: Elek Science.Google Scholar
Waterston, C. D. 1964. Observations on pterygotid eurypterids. TRANS R SOC EDINBURGH 66, 9–33.CrossRefGoogle Scholar
Waterston, C. D. 1979. Problems of functional morphology and classification in stylonuroid eurypterids (Chelicerata, Merostomata), with observations on the Scottish Silurian Stylonuroidea. TRANS R SOC EDINBURGH 70, 251–322.Google Scholar
Whittington, H. B. 1975. Trilobites with appendages from the Burgess Shale, Middle Cambrian, British Columbia. FOSSILS AND STRATA 4, 97–136.CrossRefGoogle Scholar
Whittington, H. B. 1980. Exoskeleton, moult stage, appendage morphology, and habits of the Middle Cambrian trilobite Olenoides serratus. PALAEONTOLOGY 23, 171–204.Google Scholar
Wills, L. J. 1965. A supplement to Gerhard Holm's “Uber die Organisation des Eurypterus fischeri Eichw”.with special reference to the organs of sight, respiration and reproduction. ARK ZOOL 18, 93–145.Google Scholar
Wyse, G. A. & Dwyer, N. K. 1973. The neuromuscular basis of coxal feeding and locomotory movements in Limulus. BIOL BULL MAR BIOL LAB WOODS HOLE 144, 567–79.CrossRefGoogle Scholar
Zug, G. R. 1971. Buoyancy, locomotion, morphology of the pelvic girdle and hindlimb and systematics of cryptodiran turtles. MISC PUBL MUS ZOOL UNIV MICHIGAN 142, 1–98.Google Scholar