ISSN:
1432-234X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The architecture of the body cuticle of juvenile Aporcelaimellus is identical to that of the adult, but the infracuticle is absent in the first stage juvenile. The cuticle is composed of fiber layers that are separated and perforated by a lacunar system. The lacunae are thought to contribute to the flexibility of the cuticle. The hypodermis is cellular. The cell-to-cell contacts consist of convoluted membranes that are often fortified by zonulae adhaerentes. The first moult was studied in specimens in the A1- and A5-stage (terminology of Coomans and van der Heiden, 1971). A stage chronologically prior to the A1-stage was found, which is referred to as A0-stage in this paper. During the A0-stage, the hypodermal cells become hypertrophic and gland-like. The zonulae adhaerentes seem to be replaced by septate desmosomes. The cuticle separates from the hypodermis. Cuticle-formation is in progress during the A1-stage. The outer layers of the new cuticle are laid down by the hypodermal cells underneath the old cuticle. Projections from the epithelium become enclosed within the new cuticle. Cuticle-secretion is completed during the A5-stage, but hardiy any differentiation is discernable. At the end of the A5-stage differentiation initiates by condensation of the filamentous material. The hypodermal projections gradually retract from the cuticle. It is concluded that the lacunar system originates from the differentiation-process. No evidence was found for partial resorption of the old cuticle.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00277509
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