ULTRASTRUCTURE OF ANTERIOR BODY REGION OF MARINE NEMATODE DEONTOSTOMA-CALIFORNICUM

  • 1 January 1977
    • journal article
    • research article
    • Vol. 9  (1) , 56-82
Abstract
The ultrastructure of the anterior body region of the free-living marine nematode D. californicum was studied by EM. The body wall consists of a 9-layered cuticle, a cellular hypodermis containing 8 nerve bundles and a well-developed coelomyarian somatic musculature. Nerves in the dorsal, lateral, ventral and submedian hypodermal chords anterior to the nerve ring were observed with regularity. Structure of subventral somatic setae suggests a mechanoreceptive function. The esophagus is cellular and consists of 3 marginal cells alternating with an equal number of radial muscle cells, 3 esophageal glands, and 3 enteric nerves. The membranes of adjacent esophageal cells are sinuous. Apices of the triradiate lumen are connected with the outer wall of each marginal cell by bands of electron-dense non-myofibrils, whereas 2 types of myofilaments run radially between the apophyses of the lumen and the outer walls of radial cells. Each myofibril, which forms hemidesmosomes at both ends, is interpreted to be the morphological equivalent of 1 sarcomere. Synaptic junctions between the processes of muscles, gland cells and axons of the enteric nerves are described in detail.

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