Skip to main content
Log in

Non-respiratory podia of clypeasteroids (Echinodermata, Echinoides)

I. Functional anatomy

  • Published:
Zoomorphology Aims and scope Submit manuscript

Summary

The podia found in the Order Clypeasteroida are composed of three basic systems: (1) a specialized external epithelium, (2) a connective tissue sheath enclosing a hydrostatic skeleton, (3) an intrinsic smooth muscle system. The components of each system are described using histology and scanning electron microscopy and their particular functions are elucidated. The external epithelium is specialized at the tip and supports short cilia on the disk and diaphragm, and long cilia on the periphery of the disk. The epidermis is covered by a mucous layer (approximately 1 μm), that is studded by microvilli-like projections. Two types of secretory cells are present in the tips of all suckered podia. Small secretory cells amongst the disk muscles produce adhesive substances. Large secretory cells of the podial disk periphery are described in the Clypeasteroida for the first time. Secretions from these cells are used during sucker attachment, and as binding material for food particles. Dissections of podia display the arrangement of fibres that constitute the collagenous connective tissue sheath and its relationship to the podial nerve. Longitudinal connective tissue is found in three bundles running the length of the podium. Circular connective tissue forms a continuous sheath separating lumen musculature and coelomic epithelium from the external epithelium. Disk and radial connective tissue fibres maintain the shape of the tip and help transmit forces from the various podial muscles. Spicules perform a similar function. Stem retractor and levator muscles are found just inside the connective tissue sheath. Disk and diaphragm muscles outside the sheath (along with the levators) operate the tip during particle manipulations. Descriptions of these activities, based on live observations and scanning electron microscope studies of mucous prints, are provided. Podia develop as heavily nucleated buds of epithelium growing at the exits of podial canals through the test. The tip and connective tissues differentiate before the nervous tissue, muscles, and secretory cells. Clypeasteroid suckered podia are shown to be most similar to those found in the Order Cassiduloida.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Agassiz A (1872–1874) Revision of the Echini. Illustrated Catalogue of the Museum of Comparative Zoology no. 7. Cambridge, Massachusetts

  • Armed Forces Institute of Pathology (1960) Manual of Histologic and Special Staining Technics, 2nd ed. McGraw-Hill, New York, pp 207

    Google Scholar 

  • Burke RD (1980) Podial sensory receptors and the induction of metamorphosis in echinoids. J Exp Mar Biol Ecol 47:223–234

    Google Scholar 

  • Chia FS (1969) Some observations on the locomotion and feeding of the sand dollar, Dendraster excentricus (Eschscholtz). J Exp Mar Biol Ecol 3:162–170

    Google Scholar 

  • Coleman R (1969) Ultrastructure of the tube foot sucker of a regular echinoid, Diadema antillarum Philippi, with especial reference to secretory cells. Z Zellforsch mikrosk Anat 96:151–161

    Google Scholar 

  • Durham JW (1955) Classification of clypeasteroid echinoids. Univ Calif Publ Geol Sci 31:73–198

    Google Scholar 

  • Ehlers U, Ehlers B (1978) Paddle cilia and discocilia-genuine structures? Cell Tiss Res 192:489–501

    Google Scholar 

  • Engster MS, Brown SC (1972) Histology and ultrastructure of the tube foot epithelium in the phanerozonian starfish, Astropecten. Tissue and Cell 4:503–518

    Google Scholar 

  • Fenner DH (1973) The respiratory adaptations of the podia and ampullae of echinoids (Echinodermata). Biol Bull 145:323–339

    Google Scholar 

  • Florey E, Cahill MA (1977) Ultrastructure of sea urchin feet. Evidence for connective tissue involvement in motor control. Cell Tiss Res 177:195–214

    Google Scholar 

  • Ghiold J (1979) Spine morphology and its significance in feeding and burrowing in the sand dollar, Mellita quinquiesperforata (Echinodermata: Echinoidea). Bull Mar Sci 29:481–490

    Google Scholar 

  • Hermans C (1983) The duo-gland adhesive system. Oceanogr Mar Biol Ann Rev 21:283–339

    Google Scholar 

  • Hidaka M, Takahashi K (1983) Fine structure and mechanical properties of the catch apparatus of the sea-urchin spine, a collagenous connective tissue with muscle-like holding capacity. J Exp Biol 103:1–14

    Google Scholar 

  • Holland NG, Nealson KH (1978) The fine structure of the echinoderm cuticle and subcuticular bacteria of echinoderms. Acta Zool (Stockholm) 59:169–185

    Google Scholar 

  • Humason GL (1962) Animal tissue techniques. WH Freeman, San Francisco, pp 569

    Google Scholar 

  • Kier PM (1974) Evolutionary trends and their functional significance in the post-Paleozoic echinoids. J Paleont 48(suppl): Paleont Soc Mem 5:1–95

    Google Scholar 

  • MacBride EW (1909) Echinodermata. In: Hamer SF, Shipley AE (eds) Cambridge Natural History, MacMillan, London, pp 425–623

    Google Scholar 

  • Mooi R (1983) Morphology, diversity and function of non-respiratory podia of clypeasteroids (Echinodermata: Echinoidea). MSc Dissertation, University of Toronto, pp 106

  • Mooi R (1985) Non-respiratory podia of clypeasteroids (Echinodermata: Echinoidea): II. Diversity. Zoomorphology 106:in press

  • Mooi R, Telford M (1982) The feeding mechanism of the sand dollar Echinarachnius parma (Lamarck). Proc Int Echinoderms Conference, Tampa Bay (1981), pp 51–56

  • Nichols D (1959a) The histology of the tube-feet and clavulae of Echinocardium cordatum. Quart J Micr Sci 100:73–87

    Google Scholar 

  • Nichols D (1959b) The histology and activities of the tube-feet of Echinocyamus pusillus. Quart J Micr Sci 100:539–555

    Google Scholar 

  • Nichols D (1961) A comparative histological study of the tube-feet of two regular echinoids. Quart J Micr Sci 102:157–180

    Google Scholar 

  • Nichols D (1966) Functional morphology of the water-vascular system. In: Boolootian RA (ed) Physiology of Echinodermata. John Wiley and Sons, New York, pp 219–244

    Google Scholar 

  • Parker GH, van Alstyne MA (1932) Locomotor organs of Echinarachnius parma. Biol Bull 62:195–200

    Google Scholar 

  • Phelan TF (1977) Comments on the water vascular system, food grooves, and ancestry of the clypeasteroid echinoids. Bull Mar Sci 27:400–422

    Google Scholar 

  • Rieger R (1984) Evolution of the cuticle in the lower Eumetazoa. In: Bereiter-Hahn J, Matoltsy AG, Richards KS (eds) Biology of the Integument. Vol 1. Invertebrates. Springer-Verlag, Berlin, pp 389–399

    Google Scholar 

  • Seilacher A (1979) Constructional morphology of sand dollars. Paleobiology 5:191–221

    Google Scholar 

  • Smith AB (1980) The structure, function and evolution of tube feet and ambulacral pores in irregular echinoids. Paleontology 23:39–83

    Google Scholar 

  • Smith JE (1937) The structure and function of the tube feet in certain echinoderms. J Mar Biol Ass UK 22:345–357

    Google Scholar 

  • Smith JE (1947) The activities of the tube feet of Asterias rubens L. 1. The mechanics of movement and of posture. Quart J Micr Sci 88:1–14

    Google Scholar 

  • Stahly G, Stahly S (1981) The sand dollar book. The Artisan, Florida, pp 32

    Google Scholar 

  • Telford M, Harold AS, Mooi R (1984) Feeding structures, behavior and microhabitat of Echinocyamus pusillus (Echinoidea: Clypeasteroida). Biol Bull 165:745–757

    Google Scholar 

  • Wood RL, Cavey MJ (1981) Ultrastructure of the coelomic lining in the podium of the starfish Stylasterias forreri. Cell Tiss Res 218:449–473

    Google Scholar 

  • Woodley JD (1980) The biomechanics of ophiuroid tube-feet. Proc European Coloquium on Echinoderms, Brussels (1979), pp 293–299

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Mooi, R. Non-respiratory podia of clypeasteroids (Echinodermata, Echinoides). Zoomorphology 106, 21–30 (1986). https://doi.org/10.1007/BF00311943

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00311943

Keywords

Navigation