Studies on the ultrastructure of the integument of the rotifer Habrotrocha rosa Donner (Aschelminthes)

Summary The integument of the rotifer Habrotrocha rosa Donner is provided with pores and formed by an extrasyncytial cuticle and a syncytial hypodermis. The hypodermis peripherally contains 3 layers of dense cytoplasm and borders the cuticle by an asymmetric cell membrane. The wall of the pores is stiffened proximally like an annulus. The pores lead into cytoplasmic invaginations which are surrounded by vesicles. Close to and also beneath the condensed cytoplasmic layers microbodies are found, which are interpreted as microperoxisomes. Subhypodermal layers of muscles are connected with the cytoplasm of the hypodermis by desmosome-like structures.I am indebted to Dr. H. Breucker, Anatomisches Institut Hamburg, and Prof. Dr. W. Becker, Zoologisches Institut Hamburg, under whose direction this work was carried out. Supported by the Deutsche Forschungsgemeinschaft (Be 464/10)     

An ultrastructural approach to feeding behaviour in Philodina roseola and Brachionus calyciflorus (rotifers) II. The oesophagus

The cuticular oesophagus is a simple expansion of the dorsal pharyngeal wall of the mastax. The ciliary oesophagus is the cellular anterior wall of the stomach lumen, but seems to have the same embryological origin as the pharynx.In Brachionus calyciflorus, its cilia are surrounded by cuticular velums which have the same myelin-like structure and the same function as the buccal velum of Philodina roseola. In all cases, the oesophagus prevents the return of food particles from the stomach to the mastax lumen.