Ultrastructure of the Tegument of Intramolluscan Stages of Proterometra Edneyi Nomen Nudum

Larval stages of Proterometra edneyi nomen nudum were obtained from Goniobasis laqueata and prepared for transmission and scanning electron microscopy. The tegument of rediae, cercariae within rediae and mature cercariae were observed to see if any differences occurred in relation to enivronmental and functional factors. The tegument was found to be similar in organization to that previously reported for other trematodes. Rediae were found to have patterned, folded teguments with many small microvilli indicative of the function of this surface to absorb nutrients. Microvilli were also present on the tegument of the cercarial body within the rediae along with infoldings for increased surface area. Tegument of the mature cercarial body was smooth, reflecting the change in nutrient acquisition at maturity. Papillae, probably sensory in function, were present on the anterior portion of the cercarial tail. as seen with transmission electron microscopy, the tegument in this area seemed more vesicular than in other areas. The tegument of the stem region was composed of many projections which would increase the surface aiding in absorption of nutrients. This increased surface area could also be involved with respiratory exchange once outside of the snail. The tegument of the furcae was invaginated and the interior appeared more muscular, relating to their locomotive function. The tegumental differences observed in P. edneyi appeared to correspond to the environment and functional states of the larval stages