The ultrastructure of the cuticle of the nematode Syphacia obvelata (Rudolphi, 1802). I. The body cuticle of larvae, males,and females, and observations on its development

Abstract

The body cuticle of Syphacia obvelata (Rudolphi, 1802) has been examined with light and electron microscopy through larval and adult stages. In all stages the cuticle consists of a cortex, and median and basal zones. Material showing transverse striations with 180–220 Å periodicity (striated material) occurs in the median zone of larvae and young adults. However, progressive growth and deposition of more striated material results in the cuticle of older females appearing markedly different from the cuticle of the short-lived males. Striated material is concluded to be formed of bands of approximately circular discs. Overlap of such bands produces the various patterns seen in sections. Similarities between methods of formation of striated material and other cuticular components are noted between molting periods and the growth phase of females. The presence of intracuticular tubules and external longitudinal ridges is noted.