[The filaria Cercopithifilaria roussilhoni in the tick vector]

Histological and ultrastructural analysis of the development of C. roussilhoni--a filarial parasite of A. africanus with skin-dwelling microfilariae--in the hexapod, larva of R. sanguineus. The development takes place in the epidermis. The intra-epidermal development, which is rare in the Spirurida, is known in a close filaria, also transmitted by Ixodids, Monanema martini. The slow development of C. roussilhoni and the pronounced changes of the parasitized epidermal syncytium (very large nuclei; expanding nuclear envelop and cellular membrane which form complicated expansions; many dilatations of the endoplasmic reticulum) demonstrate the more primitive state of this filaria.