Gonospora minchinii, N. sp.,a Gregarine 
inhabiting the egg of Arenicola. 
By 
Edwin 8. Goodrich, F.R.S., and H. L. M. Pixell Goodrich, D.Se. 
With Plates 5 and 6. 
Wuen examining the contents of the coelom of an Areni- 
cola ecaudata Johnston, at the Marine Biological Labora- 
tory in Plymouth last winter, we discovered a new Gregarine 
of considerable interest, since it appears to be the first instance 
on record of such a parasite inhabiting the ovum of its host.4 
This gregarine belongs to the genus Gonospora. It does not 
seem to occur at all in the male worm, and of the females 
examined only about 30 per cent. were infected. However, 
since the parasite was not found in any but female worms whose 
ovaries were fairly ripe and had begun to shed their products 
into the coelom, it is probable that it often inhabits less mature 
hosts, but in some situation not yet determined. We have 
looked for it without success in the immature ovary. Frequently 
it occurs simultaneously with the larger and well-known coelomic 
cregarine Gonospora (Kalpidorhynehus) areni- 
colae Cunningham. 
The immature ovary of Arenicola ecaudata isa lobu- 
lated organ with finger-shaped processes (see Gamble and Ash- 
worth, 1). Inside it the germ-cells multiply, accumulating in its 
lumen, and later bursting through its wall. The ova thus escape 
into the coelom at various stages in development ; some quite 
small and oval, others larger, more rounded, loaded with yolk, 
and surrounded by a thick covering. his shell is formed of two 
1 Since this was written we have learnt from Sir Ray Lankester that 
many years ago he discovered a somewhat similar parasite in the eggs of 
Thalassema. From an inspection of some unpublished drawings of the 
trophozoite, which he kindly sent to us, we conclude that it is not the 
Gregarine described in this paper. 
