Quarterly Journal of Microscopical Science, Vol s2-65, 157-162, Copyright © 1920 by Company of Biologists

Memoirs: Gonospora minchinii, n. sp., a Gregarine inhabiting the egg of Arenicola

The new species of gregarine described above, and to which we have given the name Gonospora minchinii, occurs in the coelomic fluid of the female Arenicolaecaudata. The adult trophozoite is pear-shaped, and the ripe spore has a thin cyst without distinct funnel. The young trophozoite lives in the egg floating in the coelomic fluid of the Arenicola, where it grows at the expense of the food-material stored in the ovum. To reach the ovum it pierces the vitelline membrane and perivitelline layer. The growing trophozoite occupies a deep depression it causes in the egg, to which it adheres by its epimerite. The margin of this depression becomes drawn out into delicate protoplasmic processes. The cytoplasm and nucleus of the host-cell, and also the development of the perivitelline layer, are affected by the presence of the parasite. When full-grown the trophozoite escapes from the egg by a hole pierced in its envelopes, and leucocytes then enter the space so left to complete the destruction of the ovum.