RESUMEN
1. Adult Schistosoma mansoni show a proclivity to release fragments of the tegumental surface membrane when they are incubated in various media, or after they are exposed to posirively chaged microspheres. Scanning electron microscopy was used to examine the extent and nature of the pertubations induced by the two treatment used to prepare tegumental membranes. Incubation of the parasites in a phosphate - buffered medium resulted in extensive blebbing and release of vesicles from the tegument. 3. Attachment of positively charged microspheres followed by their release yelded tegument membrane fragments of a different morphology. 4. The nature and implications of these pertubations to membrane processes occuring at the tegument of schistosomes are discussed