M archantiales. 
ioi 
Boschia lags behind Corsinia in the organisation of the sexual 
receptacles, hut advances upon it in the structure of the thallus, of 
the capsule-wall, and of the sterile cells in the capsule. 
Fij;. 10. Boschia Weddclli. Longitudinal sections of thallus. A shows 
the hood-like scale arising behind an archegonium ; B, a later stage, with a 
young sporogonium. After Leitgeb. 
This little group is of great interest, being transitional in various 
respects between the Ricciaceae and the higher Marchantiales. One 
of the most interesting features is the formation of a special out¬ 
growth for the protection of the young sporophyte. In the hood 
which arises behind the archegonial group in Boschia we have a 
structure which may be compared with the two-valved involucre of 
