MIGRATION AND DEVELOPMENT OF MOTHER SPOROCYSTS OF ECHINOSTOMA-CAPRONI(DIGENEA, ECHINOSTOMATIDAE)

Experimental infections of the mollusc Biomphalaria pfeifferi by Echin ostoma caproni miracidia (Mi) were carried out in order to analyze the migration and development of mother sporocysts (MS) at 26 C. Miracidi a penetrated different parts of the host's body, such as the mantle co llar, the foot and head covering (including velum and tentacles), the mantle cavity, and the oral cavity. The ventricle and common aorta wer e the final sites of infection for the mother sporocysts after migrati on. The path of migration of the sporocyst was influenced by the point of MS penetration, but in all casts the MS reached the ventricular th rough the venous system. Developmental studies showed that nr sly hatc hed Mi contained 5-7 germinal cells (the primary germinal cells) and s ome undifferentiated cells. During sporocyst development, every primar y germinal cell apparently gave rise to a redial embryo, whereas undif ferentiated cells gave rise. to both somatic and secondary generative cells. The eventual degeneration of the sporocyst seemed to cause the end of the development of this germinal material. The MS produced abou t 15 mother rediae (MR). Intramolluscan development of E. caproni MS c onsisted of 5 main periods: (1) resting, (2) migration, (3) grow th, ( 4) reproduction, and (5) degeneration. A lower temperature of 21 C aff ected the duration of each stage. However the path of sporocyst migrat ion, the pattern of their growth, and the developmental steps of the g erminal material were simile.