Structure and diversity of cestode epithelia.

Eucestodes have a simple aceolomate body structure and are conservative in terms of the numbers and nature of their cell types. Nevertheless, the cestodes form a diverse group with many strikingly different forms distinguished by the structure of their holdfasts, sexual tissues and embryos. These morphological adaptations have their origins in subtle variations in the structure of their cells and extracellular matrices. This review is concerned with the biology of eucestode epithelia and examines their structure and functions, interrelationships with other tissues, and gives insight into how their components are modified among the many taxa. Three features of cestode epithelia, namely, the occurrence of regional specialisation, microtriches and secretory components, are described. In addition, evidence is presented to suggest that some cestode epithelia are involved in developmental processes such as the nurture of embryos and maintenance of surrounding tissues.