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The Structure and Innervation of the Locomotor Muscles of Salps (Tunicata: Thaliacea)

Published online by Cambridge University Press:  11 May 2009

Q. Bone
Affiliation:
The Plymouth Laboratory
K. P. Ryan
Affiliation:
The Plymouth Laboratory

Extract

Salps swim by rhythmic contraction of the hoop-like bands of muscle which form a series of incomplete annuli along the body. The histology of these muscle bands was briefly examined by various early workers, such as Dolley (1887) and Knoll (1895), but was little known until Fedele (1932,1938) published the results of his careful investigations of a variety of species. His observations demonstrated the complexity and peculiarity of the muscle fibres forming the bands, which, as he pointed out, are in some respects comparable to those of arthropods in the arrangement of the sarcomeres. In all the species he examined, Fedele found that the muscle fibres were essentially similar in organization: a central granular core containing large nuclei was surrounded on the free borders of the fibre by a layer of myofibrils. However, this general arrangement differed in detail between different species, and Fedele recognized five types of muscle fibre, distinguishing these types upon such criteria as the fibrillar arrangement, and the disposition of the nuclei. In an earlier paper (Fedele, 1925) he had also given very clear figures of the manner in which these muscle fibres were innervated. He found that dis-crete motor end-formations occurred on the surface of the muscle bands, and that these were frequently intercalary, unlike the motor terminations of vertebrates.

Fedele's work was based upon very careful observation of living and fixed material at the light microscope level; in the present note, we extend his observations by describing the ultrastructure of these curious protochordate muscle fibres.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1973

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References

Barker, D., 1968. L'innervation motrice du muscle strié des vertébrés. Actualités neurophysiologiques, 8, 2371.Google Scholar
Beaulaton, J. M., 1964. Sur Paccumulation intramitochondrial de glycogéne dans la glande prothoracique du Ver à soie dur Chêne Antheraea pernyi (Guér) pendant les quatrième et cinquième stades larvaires. Compte rendu hebdomadaire des séances de I'Académie des sciences, 258, 4139–41.Google Scholar
Bone, Q., 1959. Observations upon the nervous systems of pelagic tunicates. Quarterly Journal of Microscopical Science, 100, 167–81.Google Scholar
Bogoraze, D. & Tuzet, O., 1969. Ultrastructure du muscle de la queue de l'appendiculaire Oikopleura longicauda Vogt. Les limites cellulaires; les disques intercalaires. Cahiers de biologie marine, 10, 365–74.Google Scholar
Cavey, M. J. & Cloney, R. A., 1972. The structure and differentiation of ascidian muscle. Differentiated caudal musculature of Distaplia occidentalis tadpoles. Journal of Morphology, 138, 349–74.CrossRefGoogle ScholarPubMed
Chapman, D. M., 1973. Cnidarian histology. In Outlooks in Coelenterate Biology (ed. H., Lenhoff and L., Muscatine). London, New York: Academic Press. (In Press.)Google Scholar
Dolley, C. S., 1887. On the histology of Salpa. Proceedings of the Academy of Natural Sciences of Philadelphia, 3, 298308.Google Scholar
Fedele, M., 1925. Contributo alia conoscenza dei rapporti neuro-muscolari. Le espansioni motrici intercalari nei Thaliacea. Bollettino della Societd di naturalisti di Napoli, 37, 250–7.Google Scholar
Fedele, M., 1932. Muscoli ed attivitá muscolare nei Thaliacea. Bollettino della Società di naturalisti di Napoli, 44, Atti, 237.Google Scholar
Fedele, M., 1938. Per una migliore conoscenza comparativa della fibra muscolare striata. La muscolatura somatica dei Thaliacea studiata dal punto di vista strutturale ed etologico. Archivio zoologico italiano, 25, 385436.Google Scholar
Flood, P. R., 1968. Structure of the segmental trunk muscle in amphioxus with note on the course and ‘ endings’ of the so-called ventral root fibres. Zeitschrift fur Zellforschung und mikroskopische Anatomie, 84, 398416.Google Scholar
Franzini-Armstrong, C., 1970. Studies of the triad. I. Structure of the junction in frog twitch fibres. Journal of Cell Biology, 47, 488–99.CrossRefGoogle Scholar
Garstang, W., 1928. The morphology of the Tunicata, and its bearings on the phylogeny of the Chordata. Quarterly Journal of Microscopical Science, 72, 51187.Google Scholar
Heron, A. C., 1972. Population ecology of a colonizing species: the pelagic tunicate Thalia democratica. I. Individual growth rate and generation time. Oecologia, 10, 269–93.CrossRefGoogle ScholarPubMed
Ishikawa, T. & Pei, Y. F., 1965. Intramitochondrial glycogen particles in rat retinal receptor cells. Journal of Cell Biology, 25, 402–7.CrossRefGoogle ScholarPubMed
Knoll, Ph., 1895. Einige Bemerkungen zur Lehre von der Beschaffenheit und Function der Muskelfasern. Lotos, Neu Folge, 15, 2535.Google Scholar
Lentz, T. H. L., 1966. Cell Biology of Hydra, pp. 1164. Amsterdam: North Holland Publishing Company.Google Scholar
Marchant, R. & Moore, R. T., 1973. Lomasomes and plasmalemmasomes in fungi. Protoplasma, 76, 235–47.CrossRefGoogle Scholar
Oliphant, L. W. & Cloney, R. A., 1972. The ascidian myocardium: sarcoplasmic reticulum and excitation-contraction coupling. Zeitschrift für Zellforschung und mikroskopische Anatomie, 129, 395412.CrossRefGoogle ScholarPubMed
Palmgren, A., 1948. A rapid method for selective silver staining of nerve fibres and nerve endings in mounted paraffin sections. Ada zoologica, 29, 377–92.CrossRefGoogle Scholar
Reynolds, E. S., 1963. The use of lead citrate at high pH as an electron opaque stain in electron microscopy. Journal of Cell Biology, 17, 208–12.CrossRefGoogle ScholarPubMed
Tannenbaum, A. D. & Rosenbluth, J., 1972. Myoneural junctions in larval ascidian tail. Experientia, 28, 1210–12.CrossRefGoogle ScholarPubMed