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Organic preservation of non-mineralizing organisms and the taphonomy of the Burgess Shale

Published online by Cambridge University Press:  08 April 2016

Nicholas J. Butterfield
Nicholas J. Butterfield*
Affiliation:
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138
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Abstract

Organic preservation of non-mineralizing animals constitutes an important part of the paleontological record, yet the processes involved have not been investigated in detail. Organic-walled fossils are generally explicable as a coincidence of original, relatively recalcitrant, extra-cellular materials and more or less anti-biotic depositional circumstances. One of the most pervasive natural inhibitors of biodegradation results from substrate and enzyme adsorption onto, and within, clay minerals; such interactions are likely responsible for many of the organic-walled fossils preserved in clastic sediments. Close examination of the fossil Lagerstätte of the Burgess Shale (Middle Cambrian, British Columbia) reveals that most of its so-called soft-bodied fossils are composed of primary (although kerogenized) organic carbon. Their preservation can be attributed to pervasive clay-organic interactions as the organisms were transported in a moving sediment cloud and buried with all cavities and spaces permeated with fine grained clays. The organic-walled Burgess Shale fossils were studied both in petrographic thin section and isolated from the rock matrix, following careful acid maceration. Isotopic analysis of bulk organic and carbonate carbon yielded values consistent with a normal marine paleoenvironment. Anatomical and histological consideration of the enigmatic Burgess worm Amiskwia suggest that it may in fact be a chaetognath, while the putative chordate Pikaia appears not to be related to modern cephalochordates.

Type
Research Article
Information
Paleobiology , Volume 16 , Issue 3 , Summer 1990 , pp. 272 - 286
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Ahnelt, P. 1984. Minor coelomate phyla. Chaetognatha. Pp. 746–755. In Bereiter-Hahn, J., Matoltsy, A. G., and Richards, K. S. (eds.), Biology of the Integument, Volume 1, Invertebrates. Springer-Verlag; Berlin.CrossRefGoogle Scholar
Alexander, M. 1965. Biodegradation: problems of molecular recalcitrance and microbial fallibility. Advances in Applied Microbiology 7:35–80.CrossRefGoogle ScholarPubMed
Alexander, M. 1973. Nonbiodegradable and other recalcitrant molecules. Biotechnology and Bioengineering 15:611–647.Google Scholar
Allison, F. E., Sherman, M. S., and Pinck, L. A. 1949. Maintenance of soil organic matter: inorganic soil colloid as a factor in retention of carbon during formation of humus. Soil Science 68:463–478.Google Scholar
Allison, P. A. 1988a. Konservat-Lagerstätten: cause and classification. Paleobiology 14:331–344.CrossRefGoogle Scholar
Allison, P. A. 1988b. The role of anoxia in the decay and mineralization of proteinaceous macro-fossils. Paleobiology 14:139–154.Google Scholar
Bartram, K. M., Jeram, A. J., and Selden, P. A. 1987. Arthropod cuticles in coal. Journal of the Geological Society, London 144:513–517.CrossRefGoogle Scholar
Beauchamp, B., Krouse, H. R., Harrison, J. C., Nassichuk, W. W., and Eliuk, L. S. 1989. Cretaceous cold-seep communities and methane-derived carbonates in the Canadian arctic. Science 244:53–56.Google Scholar
Bengtson, S. 1986. Introduction: the problem of the problematica. Pp. 3–11. In Hoffman, A., and Nitecki, M. H. (eds.), Problematic Fossil Taxa. Oxford University Press; New York.Google Scholar
Bengtson, S., and Urbanek, A. 1986. Rhabdotubus, a Middle Cambrian rhabdopleurid hemichordate. Lethaia 19:293–308.CrossRefGoogle Scholar
Benoit, R. E., and Starkey, R. L. 1968. Enzyme inactivation as a factor in the inhibition of decomposition of organic matter by tannins. Soil Science 105:203–208.CrossRefGoogle Scholar
Bereiter-Hahn, J. 1984. The protochordates. Cephalochordata. Pp. 817–825. In Bereiter-Hahn, J., Matoltsy, A. G., and Richards, K. S. (eds.), Biology of the Integument, Volume 1, Invertebrates. Springer-Verlag; Berlin.CrossRefGoogle Scholar
Bereiter-Hahn, J., Matoltsy, A. G., and Richards, K. S. (eds.). 1984. Biology of the Integument, Volume 1, Invertebrates. Springer-Verlag; Berlin.Google Scholar
Bertrand, R., and Héroux, Y. 1987. Chitinozoan, graptolite, and scolecodont reflectance as an alternative to vitrinite and pyrobitumen reflectance in Ordovician and Silurian strata, Anticosti Island, Quebec, Canada. American Association of Petroleum Geologists Bulletin 71:951–957.Google Scholar
Bradley, W. H. 1931. Origin and microfossils of the oil shale of the Green River Formation of Colorado and Utah. United States Geological Survey Professional Paper 168.Google Scholar
Briggs, D. E. G. 1978. A new trilobite-like arthropod from the Lower Cambrian Kinzers Formation, Pennsylvania. Journal of Paleontology 52:132–140.Google Scholar
Briggs, D. E. G., and Conway Morris, S. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia. Pp. 167–183. In Hoffman, A., and Nitecki, M. H. (eds.), Problematic Fossil Taxa. Oxford University Press; New York.Google Scholar
Briggs, D. E. G., and Fortey, R. A. 1989. The early radiation and relationships of the major arthropod groups. Science 246:241–243.Google Scholar
Briggs, D. E. G., and Mount, J. D. 1982. The occurrence of the giant arthropod Anomalocaris in the lower Cambrian of southern California, and the overall distribution of the genus. Journal of Paleontology 56:1112–1118.Google Scholar
Briggs, D. E. G., and Robison, R. A. 1984. Exceptionally preserved nontrilobite arthropods and Anomalocaris from the Middle Cambrian of Utah. University of Kansas Paleontological Contributions 111.Google Scholar
Brooks, H. K. 1965. Arthropods with chitinous exoskeletons. Pp. 64–75. In Kummel, B., and Raup, D. (eds.), Handbook of Paleontological Techniques. W. H. Freeman & Company; San Francisco.Google Scholar
Burns, R. G. 1979. Interaction of microorganisms, their substrates and their products with soil surfaces. Pp. 109–138. In Ellwood, D. C., Melling, J., and Rutter, P. (eds.), Adhesion of Microorganisms to Surfaces. Academic Press; London.Google Scholar
Butterfield, N. J. 1990. A reassessment of the enigmatic Burgess Shale fossil Wiwaxia corrugata (Matthew) and its relationship to the polychaete Canadia spinosa Walcott. Paleobiology 16:287–303.Google Scholar
Butterfield, N. J., Knoll, A. H., and Swett, K. 1988. Exceptional preservation of fossils in an Upper Proterozoic shale. Nature 334:424–427.CrossRefGoogle Scholar
Chamley, H. 1989. Clay Sedimentology. Springer-Verlag; Berlin.Google Scholar
Chaney, R. W. 1959. Miocene floras of the Columbia Plateau, Part I. Composition and interpretation. Carnegie Institution of Washington Publication 617:1–134.Google Scholar
Chapman, R. F. 1985. Structure of the digestive system. Pp. 165–211. In Kerkut, G. A., and Gilbert, L. I. (eds.), Comprehensive Insect Physiology, Biochemistry, and Pharmacology, Volume 4. Pergamon Press; Oxford.Google Scholar
Conway Morris, S. 1977a. Fossil priapulid worms. Special Papers in Palaeontology 20.Google Scholar
Conway Morris, S. 1977b. A redescription of the Middle Cambrian worm Amiskwia sagittiformis Walcott from the Burgess Shale of British Columbia. Paläontologische Zeitschrift 51:271–287.Google Scholar
Conway Morris, S. 1979. Middle Cambrian polychaetes from the Burgess Shale of British Columbia. Philosophical Transactions of the Royal Society of London B 285:227–274.Google Scholar
Conway Morris, S. 1986. The community structure of the Middle Cambrian Phyllopod Bed (Burgess Shale). Palaeontology 29:423–467.Google Scholar
Conway Morris, S. 1989. Burgess Shale faunas and the Cambrian explosion. Science 246:339–346.Google Scholar
Conway Morris, S., and Robison, R. A. 1988. More soft-bodied animals and algae from the Middle Cambrian of Utah and British Columbia. University of Kansas Paleontological Contributions 122.Google Scholar
Conway Morris, S., and Whittington, H. B. 1979. The animals of the Burgess Shale. Scientific American 241(1):122–133.Google Scholar
Crowther, P. R. 1981. The fine structure of graptolite periderm. Special Papers in Palaeontology 26.Google Scholar
Dalingwater, J. E. 1975. Further observations on eurypterid cuticles. Fossils and Strata 4:271–279.CrossRefGoogle Scholar
Dennell, R. 1949. Earthworm chaetae. Nature 164:370.Google Scholar
DeNiro, M. J., and Epstein, S. 1978. Influence of diet on the distribution of carbon isotopes in animals. Geochimica et Cosmochimica Acta 42:495–506.Google Scholar
Emerson, S., and Hedges, J. I. 1988. Processes controlling the organic carbon content of open ocean sediments. Paleoceanography 3:621–634.Google Scholar
Ferris, F. G., Fyfe, W. S., and Beveridge, T. J. 1988. Metallic ion binding by Bacillus subtilis: implications for the fossilization of microorganisms. Geology 16:149–152.2.3.CO;2>CrossRefGoogle Scholar
Foree, E. G., and McCarty, P. L. 1970. Anaerobic decomposition of algae. Environmental Science and Technology 4:842–849.Google Scholar
Garwood, G. A., Mortland, M. M., and Pinnavaia, T. J. 1983. Immobilization of glucose oxidase on montmorillonite clay: hydrophobic and ionic modes of binding. Journal of Molecular Catalysis 22:153–163.Google Scholar
Gibson, R. 1984. Aceolomata. Nemertea. Pp. 205–211. In Bereiter-Hahn, J., Matoltsy, A. G., and Richards, K. S. (eds.), Biology of the Integument, Volume 1, Invertebrates. Springer-Verlag; Berlin.Google Scholar
Glaessner, M. F. 1979. Lower Cambrian Crustacea and annelid worms from Kangaroo Island, South Australia. Alcheringa 3:21–31.Google Scholar
Golenberg, E. M., Giannasi, D. E., Clegg, M. T., Smiley, C. J., Durbin, M., Henderson, D., and Zurawski, G. 1990. Chloroplast DNA sequence from a Miocene Magnolia species. Nature 344:656–658.CrossRefGoogle ScholarPubMed
Goodarzi, F., and Norford, B. S. 1989. Variation of graptolite reflectance with depth of burial. International Journal of Coal Geology 11:127–141.Google Scholar
Goodrich, E. S. 1896. Notes on oligochaetes, with the description of a new species. Quarterly Journal of Microscopical Science 39:51–69.Google Scholar
Goodwin, S., and Zeikus, J. G. 1987. Ecophysiological adaptations of anaerobic bacteria to low pH: analysis of anaerobic digestion in acidic bog sediments. Applied and Environmental Microbiology 53:57–64.Google Scholar
Gould, S. J. 1989. Wonderful Life. W. W. Norton; New York.Google Scholar
Gustus, R. M., and Cloney, R. A. 1973. Ultrastructure of the larval compound setae of the polychaete Nereis vexillosa Grube. Journal of Morphology 140:355–366.Google Scholar
Hackman, R. H. 1971. The integument of Arthropoda. Pp. 1–62. In Florkin, M., and Scheer, B. T. (eds.), Chemical Zoology, Volume VIB, Arthropoda. Academic Press; New York.Google Scholar
Hackman, R. H., and Goldberg, M. 1968. A study of a melanic mutant of blowfly Lucilia cuprina. Journal of Insect Physiology 14:765–775.CrossRefGoogle Scholar
Hammer, C. U., Clausen, H. B., and Dansgaard, W. 1980. Greenland ice sheet evidence of post-glacial volcanism and its climatic impact. Nature 288:230–235.Google Scholar
Haskå, G. 1981. Activity of bacteriolytic enzymes adsorbed to clays. Microbial Ecology 7:331–341.CrossRefGoogle ScholarPubMed
Holland, H. D. 1984. The Chemical Evolution of the Atmosphere and Oceans. Princeton University Press; Princeton.CrossRefGoogle Scholar
Hou, Xian-Guang. 1987. Two new arthropods from lower Cambrian Chengjiang, eastern Yunnan. Acta Palaeontologica Sinica 26:236–256.Google Scholar
Huang, L., Forsberg, C. W., and Gibbins, L. N. 1986. Influence of external pH and fermentation products on Clostridium acetobutylicum intracellular pH and cellular distribution of fermentation products. Applied and Environmental Microbiology 51:1230–1234.Google Scholar
Jacobson, S. R. 1979. Acritarchs as paleoenvironmental indicators in Middle and Upper Ordovician rocks from Kentucky, Ohio, and New York. Journal of Paleontology 53:1197–1212.Google Scholar
Jeuniaux, C. 1971. Chitinous structures. Pp. 595–632. In Florkin, M., and Stotz, E. H. (eds.), Comparative Biochemistry, Volume 26C. Elsevier; Amsterdam.Google Scholar
Kirk, T. K., and Farrell, R. L. 1987. Enzymatic “combustion”: the microbial degradation of lignin. Annual Review of Microbiology 41:465–505.Google Scholar
Kobayashi, Y., and Aomine, S. 1967. Mechanism of inhibitory effect of allophane and montmorillonite on some enzymes. Soil and Plant Nutrition (Tokyo) 13:189–194.Google Scholar
Laanbroek, H. J., and Veldkamp, H. 1982. Microbial interactions in sediment communities. Philosophical Transactions of the Royal Society of London B 297:533–550.Google Scholar
Labandeira, C. C., Beall, B. S., and Hueber, F. M. 1988. Early insect diversification: evidence from a lower Devonian bristletail from Quebec. Science 242:913–916.CrossRefGoogle Scholar
Ladd, J. N., and Butler, J. H. A. 1969. Inhibition and stimulation of proteolytic enzyme activities by soil humic acids. Australian Journal of Soil Research 7:253–261.Google Scholar
Lawrence, D. R. 1968. Taphonomy and information losses in fossil communities. Geological Society of America Bulletin 79:1315–1330.Google Scholar
Leo, R. F., and Barghoorn, E. S. 1976. Silicification of wood. Botanical Museum Leaflets, Harvard University 25.Google Scholar
Ludvigsen, R. 1989. The Burgess Shale: not in the shadow of the Cathedral Escarpment. Geoscience Canada 16:51–59.Google Scholar
MacGinitie, H. D. 1953. Fossil plants of the Florissant Beds, Colorado. Carnegie Institution of Washington Publication 599.Google Scholar
Mankiewicz, C. 1988. Obruchevella in the Middle Cambrian Burgess Shale: preservation and taxonomic affinity. Geological Society of America, Abstracts with Programs 20:A226.Google Scholar
Marshall, K. C. 1976. Interfaces in Microbial Ecology. Harvard University Press; Cambridge, Massachusetts.Google Scholar
Martill, D. M. 1988. Preservation of fish in the Cretaceous Santana Formation of Brazil. Palaeontology 31:1–18.Google Scholar
Martill, D. M., and Unwin, D. M. 1989. Exceptionally well preserved pterosaur wing membrane from the Cretaceous of Brazil. Nature 340:138–140.CrossRefGoogle Scholar
McLaughlin, P. A. 1983. Internal anatomy. Pp. 1–52. In Bliss, D. E., and Mantel, L. H. (eds.), The Biology of the Crustaceans, Volume 5, Internal Anatomy and Physiological Regulation. Academic Press; New York.Google Scholar
Michel, C., and Devillez, E. J. 1978. Digestion. Pp. 509–554. In Mill, P. J. (ed.), Physiology of Annelids. Academic Press; London.Google Scholar
Mikulic, D. G., Briggs, D. E. G., and Kluessendorf, J. 1985. A new exceptionally preserved biota from the Lower Silurian of Wisconsin, U.S.A. Philosophical Transactions of the Royal Society of London B 311:75–85.Google Scholar
Morgan, H. W., and Corke, C. T. 1976. Adsorption, desorption, and activity of glucose oxidase on selected clay species. Canadian Journal of Microbiology 22:684–693.Google Scholar
Mortland, M. M. 1984. Deamination of glutamic acid by pyridoxal phosphate-Cu2+-smectite catalysts. Journal of Molecular Catalysis 27:143–155.Google Scholar
Mortland, M. M., and Gieseking, J. E. 1952. The influence of clay minerals on the enzymatic hydrolysis of organic phosphorous compounds. Soil Science of America Proceedings 16:10–13.Google Scholar
Niklas, K. J., Brown, R. M. Jr., Santos, R., and Vian, B. 1978. Ultrastructure and cytochemistry of Miocene angiosperm leaf tissues. Proceedings of the National Academy of Sciences 75:3263–3267.Google Scholar
Norton, R. A., Bonamo, P. M., Grierson, J. D., and Shear, W. A. 1988. Oribatid mite fossils from a terrestrial Devonian deposit near Gilboa, New York. Journal of Paleontology 62:259–269.Google Scholar
Ossian, C. R. 1973. New Pennsylvanian scyphomedusan from western Iowa. Journal of Paleontology 47:990–995.Google Scholar
Owre, H. B., and Bayer, F. M. 1962. The systematic position of the Middle Cambrian fossil Amiskwia Walcott. Journal of Paleontology 36:1361–1363.Google Scholar
Peters, W., and Walldorf, V. 1986. Endodermal secretion of chitin in the ‘cuticle’ of the earthworm gizzard. Tissue and Cell 18:361–374.Google Scholar
Piper, D. J. W. 1972. Sediments of the Middle Cambrian Burgess Shale, Canada. Lethaia 5:169–175.Google Scholar
Rand, B., and Melton, I. E. 1975. Isoelectric point of the edge surface of kaolinite. Nature 257:214–216.Google Scholar
Richards, A. G., and Richards, P. A. 1977. The peritrophic membranes of insects. Annual Review of Entomology 22:219–240.CrossRefGoogle ScholarPubMed
Richards, K. S. 1978. Epidermis and cuticle. Pp. 33–61. In Mill, P. J. (ed.), Physiology of Annelids. Academic Press; London.Google Scholar
Rieger, R. M. 1984. Evolution of the cuticle in the lower eumetazoa. Pp. 389–399. In Bereiter-Hahn, J., Matoltsy, A. G., and Richards, K. S. (eds.), Biology of the Integument, Volume 1, Invertebrates. Springer-Verlag; Berlin.Google Scholar
Robison, R. A. 1969. Annelids from the Middle Cambrian Spence Shale of Utah. Journal of Paleontology 43:1169–1173.Google Scholar
Robison, R. A. 1985. Affinities of Aysheaia (Onychophora), with description of a new Cambrian species. Journal of Paleontology 59:226–235.Google Scholar
Seilacher, A. 1970. Begriff und bedeutung der Fossil-Lager-stätten. Neues Jarbuch für Geologie und Paläontologie Monatshefte 1970:34–39.Google Scholar
Seilacher, A., Reif, W.-E., and Westphal, F. 1985. Sedimentological, ecological and temporal patterns of fossil Lagerstätten. Philosophical Transactions of the Royal Society of London B 311:5–23.Google Scholar
Selden, P. A. 1981. Functional morphology of the prosoma of Baltoeuryptus tetragonophthalamus (Fischer) (Chelicerata: Eurypterida). Transactions of the Royal Society of Edinburgh: Earth Sciences 72:9–48.Google Scholar
Shear, W. A., Bonamo, P. M., Grierson, J. D., Rolfe, W. D. I., Smith, E. L., and Norton, R. A. 1984. Early land animals in North America: evidence from Devonian age arthropods from Gilboa, New York. Science 224:492–494.Google Scholar
Shear, W. A., Schawaller, W., and Bonamo, P. M. 1989. Record of Paleozoic pseudoscorpions. Nature 341:527–529.Google Scholar
Skujinš, J., Pukite, A., and McLaren, A. D. 1974. Adsorption and activity of chitinase on kaolinite. Soil Biology and Biochemistry 6:179–182.Google Scholar
Smiley, C. J., Gray, J., and Huggins, L. M. 1975. Preservation of Miocene fossils in unoxidized lake deposits, Clarkia, Idaho. Journal of Paleontology 49:833–844.Google Scholar
Stancliffe, R. P. W. 1989. Microforaminiferal linings: their classification, biostratigraphy and paleoecology, with special reference to specimens from British Oxfordian sediments. Micropaleontology 35:337–352.Google Scholar
Staplin, F. L. 1961. Reef controlled disruption of Devonian microplankton in Alberta. Palaeontology 4:392–424.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
Stotzky, G. 1980. Surface interactions between clay minerals and microbes, viruses and soluble organics, and the probable importance of these interactions to the ecology of microbes in soil. Pp. 231–249. In Berkeley, R. C. W., Lynch, J. M., Melling, J., Rutter, P. R., and Vincent, B. (eds.), Microbial Adhesion to Surfaces. Ellis Horwood Ltd.; Chichester.Google Scholar
Symonds, R. B., Rose, W. I., and Reed, M. H. 1988. Contribution of Cl- and F-bearing gases to the atmosphere by volcanoes. Nature 334:415–418.Google Scholar
Szaniawski, H. 1982. Chaetognath grasping spines recognized among Cambrian protoconodonts. Journal of Paleontology 56:806–810.Google Scholar
Tegelaar, E. W., de Leeuw, J. W., Deremme, S., and Largeau, C. 1989. A reappraisal of kerogen formation. Geochimica et Cosmochimica Acta 53:3103–3106.Google Scholar
Teigler, D. J., and Towe, K. M. 1975. Microstructure and composition of the trilobite exoskeleton. Fossils and Strata 4:137–149.Google Scholar
Theng, B. K. G. 1979. Formation and Properties of Clay-Polymer Complexes. Elsevier; Amsterdam.Google Scholar
Thompson, I. 1979. Errant polychaetes (Annelida) from the Pennsylvanian Essex fauna of northern Illinois. Palaeontographica Abteilung A 163:169–199.Google Scholar
Tissot, B. P., and Welte, D. H. 1984. Petroleum Formation and Occurrence. Second Edition. Springer-Verlag; Berlin.Google Scholar
Voss-Foucart, M. F., and Jeuniaux, C. 1972. Lack of chitin in a sample of Ordovician Chitinozoa. Journal of Paleontology 46:769–770.Google Scholar
Walcott, C. D. 1911. Middle Cambrian annelids. Cambrian Geology and Paleontology II. Smithsonian Miscellaneous Collections 57:109–144.Google Scholar
Walcott, C. D. 1919. Middle Cambrian algae. Cambrian Geology and Paleontology IV. Smithsonian Miscellaneous Collections 67:217–260.Google Scholar
Walker, S. G., Flemming, C. A., Ferris, F. G., Beveridge, T. J., and Bailey, G. W. 1989. Physiochemical interaction of Escherichia coli cell envelopes and Bacillus subtilis cell walls with two clays and ability of the composite to immobilize heavy metal from solution. Applied and Environmental Microbiology 55:2976–2984.Google Scholar
Whittington, H. B. 1971a. Redescription of Marrella splendens (Trilobitoidea) from the Burgess Shale, Middle Cambrian, British Columbia. Geological Survey of Canada Bulletin 209.Google Scholar
Whittington, H. B. 1971b. The Burgess Shale: history of research and preservation of fossils. Pp. 1170–1201. In Yochelson, E. L. (ed.), Proceedings of the First North American Paleontological Convention, Volume II. Allen Press; Lawrence, Kansas.Google Scholar
Whittington, H. B. 1974. Yohoia Walcott and Plenocaris n. gen., arthropods from the Burgess Shale, Middle Cambrian, British Columbia. Geological Survey of Canada Bulletin 231.Google Scholar
Whittington, H. B. 1985. The Burgess Shale. Yale University Press; New Haven.Google Scholar
Whittington, H. B., and Briggs, D. E. G. 1985. The largest Cambrian animal, Anomalocaris, Burgess Shale, British Columbia. Philosophical Transactions of the Royal Society of London B 309:569–609.Google Scholar
Wills, L. J. 1966. A supplement to Gerhard Holm's “Über die Organisation des Eurypterus Fischeri Eichw.” with special reference to the organs of sight, respiration and reproduction. Arkiv För Zoologi 18:93–146.Google Scholar