Summary
The nemertean Paranemertes peregrina captures prey by using an eversible proboscis that is armed with a stylet apparatus. The apparatus consists of several reserve stylet sacs and a central stylet that is attached to a granular mass, called the basis. When the proboscis is everted, the central stylet is used to stab prey such as nereid polychaetes, and paralytic neurotoxins, produced in the proboscis, are inserted in the stylet-induced wounds. The central stylet averages 85 μm in length and has helically-arranged grooves along its shaft. The proximal piece of the central stylet is anchored to the basis, apparently by adhesive granules in the anterior end of the basis. A basis sheath surrounds the basis and is continuous posteriorly with a duct, called the ductus ejaculatorius. Secretions in the ductus ejaculatorius may contain some of the toxin that is used to immobilize the prey. The contents of the duct are probably injected into the prey by way of the grooves on the central stylet. In the region anterior to the central stylet, there are numerous glandular cells and anchor cells that are believed to attach the stylet apparatus to the prey during attack. Each reserve stylet sac is lined by a simple epithelium. One of the epithelial cells, called the styletocyte, is greatly enlarged and fills the lumen of the sac. Several reserve stylets are assembled in a styletocyte. Each reserve stylet is formed within a membrane-bound vacuole associated with the Golgi apparatus and is composed of an inner organic core surrounded by an inorganic cortex. A duct connects each reserve stylet sac with the area around the central stylet and provides a pathway for the transfer of reserve stylets during replacement of the central stylet.
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References
Bacq ZM (1936) Les poisons des némertiens. Bull Cl Sci Acad Roy Belg (S) 22:1072–1079
Böhmig L (1929) Nemertini. In: Kükenthal W, Krumbach T (eds) Handbuch der Zoologie, Vol 2, Pt 1. Walter de Guyter & Co, Berlin, pp 1–110
Brocco SL, O'Clair RM, Cloney RA (1974) Cephalopod integument: the ultrastructure of Kölliker's organs and their relationship to setae. Cell Tissue Res 151:293–308
Bürger O (1895) Fauna und Flora des Golfes von Neapel, Vol XXII: Nemertinen. R Friedländer und Sohn Verlag, Berlin
Cavey M, Cloney R (1972) Fine structure and differentiation of ascidian muscle. I. Differentiated caudal musculature of Distaplia occidentalis tadpoles. J Morphol 138:349–373
Cloney RA, Florey E (1968) Ultrastructure of cephalopod chromatophore organs. Z Zellforsch Mikrosk Anat 89:250–280
Coe WR (1901) Papers from the Harriman Alaska Expedition. XX. The nemerteans. Proc Wash Acad Sci 3:1–110
Coe WR (1905) Nemerteans of the west and northwest coasts of North America. Bull Mus Comp Zool Harvard 47:1–318
Coe WR (1943) Biology of the nemerteans of the Atlantic coast of North America. Trans Conn Acad Arts Sci 35:129–328
Correa DD (1949) Ecological study of Brazilian Ototyphylonemertes. Commun Zool Mus Hist Nat Montev 3:1–7
Doe DA (1976) The proboscis hooks in Karkinorhynchidae and Gnathorhynchidae (Turbellaria, Kalyptorhynchia) as basement membrane or intracellular specializations. Zool Scr 5:105–116
Gerner L (1969) Nemertinen der Gattungen Cephalothrix und Ototyphlonemertes aus dem marinen Mesopsammal. Helgoländer Wiss Meeresunters 19:68–110
Gibbins JR, Tilney LG, Porter KR (1969) Microtubules in the formation and development of the primary mesenchyme in Arbacia punctulata I. The distribution of microtubules. J Cell Biol 41:201–226
Gibson R (1970) The nutrition of Paranemertes peregrina (Rhynchocoela: Hoplonemertea) II. Observations on the structure of the gut and proboscis, sequence of digestion, and food reserves. Biol Bull 139:92–106
Gibson R (1972) Nemerteans. Hutchinson and Co, London, p 224
Goin CJ, Goin OB, Zug GR (1978) Introduction to Herpetology. 3rd ed. WH Freeman and Co, San Francisco, p 378
Gustus RM, Cloney RA (1972) Ultrastructural similarities between setae of brachiopods and polychaetes. Acta Zool 53:229–233
Hyman LH (1951) The Invertebrates, Vol II: Platyhelminthes and Rhynchocoela. McGraw Hill Book Co, New York, pp 459–531
Kem WR (1971) A study of the occurrence of anabaseine in Paranemertes and other nemertines. Toxicon 9:23–32
Kem WR (1973) Biochemistry of Nemertine Toxins. In: Martin DF, Padilla GM (eds) Marine Pharmacognosy. Academic Press, New York, pp 37–84
Kem WR, Abbott BC, Coates RM (1971) Isolation and structure of a hoplonemertine toxin. Toxicon 9:15–22
Kirsteuer E (1977) Remarks on taxonomy and geographic distribution of the genus Ototyphylonemertes (Nemertina, Monostylifera). Mikrofauna Meeresboden 61:167–181
Ledger PW, Jones WC (1977) Spicule formation in the calcareous sponge Sycon ciliatum. Cell Tissue Res 181:553–568
Luft JH (1961) Improvements in epoxy embedding methods. J Biophys Biochem Cytol 9:409–414
Martin GG (1978) The duo-gland adhesive system of the archiannelids Protodrilus and Saccocirrus and the turbellarian Monocelis. Zoomorphologie 91:63–75
Mock H, Schmidt P (1975) Interstitielle Fauna von Galapagos XIII. Ototyphylonemertes Diesing (Nemertini, Hoplonemertini). Mikrofauna Meeresboden 51:1–40
Munger BL (1961) Staining methods applicable to sections of osmium-fixed tissue for light microscopy. J Biophys Biochem Cytol 11:502–506
O'Clair RM, Cloney RA (1974) Patterns of morphogenesis mediated by dynamic microvilli: Chaetogenesis in Nereis vexillosa. Cell Tissue Res 151:141–157
Orrhage L (1971) Light and electron microscope studies of some annelid setae. Acta Zool 52:157–169
Orrhage L (1973) Light and electron microscope studies of some brachiopod and pogonophoran setae. Z Morphol Tiere 74:253–270
Reisinger E (1926) Nemertini. Biologie Tiere Dtl 17:7.1–7.24
Reynolds ES (1963) The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol 17:208–212
Richardson KC, Jarrett L, Finke EH (1960) Embedding in epoxy resin for ultrathin sectioning in electron microscopy. Stain Technol 35:313–323
Rieger RM, Doe DA (1975) The proboscis armature of Turbellaria Kalyptorhynchia, a derivative of the basement lamina? Zool Scr 4:25–32
Roe P (1970) The nutrition of Paranemertes peregrina (Rhynchocoela: Hoplonemertea) I. Studies on food and feeding behavior. Biol Bull 139:80–91
Roe P (1976) Life history and predator-prey interactions of the nemertean Paranemertes peregrina Coe. Biol Bull 150:80–106
Roe P (1979) A comparison of aspects of the biology of Paranemertes peregrina (Nemertea) from Bodega Harbor, California and Washington State. Pacific Sci 33:281–287
Shimek RL, Kohn AJ (1981) Functional morphology and evolution of the toxoglossan radula. Malacologia 20:423–438
Simpson TL, Vaccaro CA (1974) An ultrastructural study of silica deposition in the fresh water sponge Spongilla lacustris. J Ultrastruct Res 47:296–309
Slautterback DB, Fawcett DW (1959) The development of the cnidoblasts of Hydra: An electron microscope study of cell differentiation. J Biophys Biochem Cytol 5:441–452
Tyler S (1976) Comparative ultrastructure of adhesive systems in the Turbellaria. Zoomorphologie 84:1–76
Vernick SH, Sprague V, Krause D (1977) Some ultrastructural and functional aspects of the Golgi apparatus of Thelohania sp. (Microsporidia) in the shrimp Pandalus jordani Rathbun. J Protozool 24:94–99
Westfall JA (1966) The differentiation of nematocysts and associated structures in the Cnidaria. Z Zellforsch Mikrosk Anat 75:381–403
Wourms JP (1976) Structure, composition, and unicellular origin of nemertean stylets. Amer Zool 16:213
Yamaoka T (1940) The fauna of Akkeshi Bay. IX. Nemertini. J Fac Sci Hokkaido Univ Ser 6, Zool 7:205–263
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Stricker, S.A., Cloney, R.A. The stylet apparatus of the nemertean Paranemertes Peregrina: Its ultrastructure and role in prey capture. Zoomorphology 97, 205–223 (1981). https://doi.org/10.1007/BF00310277
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DOI: https://doi.org/10.1007/BF00310277