366 Johnson. — On Steno gramme interrupta. 
gramme interrupta. In Webb’s Otia Hispanica, 1853, Mon- 
tagne gives a life-size illustration of a female plant of 5. 
interrupta , which is much more like 5 , leptophylla , J. A g., of 
which I have seen Australian specimens collected by J. B. 
Wilson, than 5 . interrupta , (C. Ag.) Mont. 
Summary . 
1. vS. interrupta is distributed through the temperate zones 
of the Northern and Southern hemispheres, extending to New 
Zealand in the south, and Scotland and the north of Ireland 
in the north. It has a well-established habitat in Plymouth 
Sound, on stones and shells, in 5-7 fathoms. 
2. Tetraspores, antheridia, and procarpia are found on dis- 
tinct plants, and on both surfaces of the thallus. 
3. The tetraspores are cruciately arranged, and occur in 
irregularly placed sori. 
4. The antheridia form broad, flat, homogeneous patches of 
spermatia. 
5. The procarpia are very numerous, of comparatively 
simple form, and have a unique position, as part of a fertile 
line extending more or less continuously along the centre of 
the thallus segments. 
6. The mother-cells of the carpogenous branches, large 
medullary cells rich in contents, constitute the auxiliary 
cells. The fertilised carpogonium becomes fused by an 
ooblastema-filament with its auxiliary cell. The resulting 
cell becomes the central cell of the developing cystocarp, and, 
after repeated divisions of its nucleus, sends out radiating 
septate, nucleated, meta-ooblastema filaments, which ultimately 
form dense aggregations of small rounded carpospores. 
7. The medullary part of the fertile line consists, before the 
procarpia are fertilised, of numerous rich cells which take no 
direct part in the formation of the cystocarps, but must con- 
tribute very materially to their development. 
8. The cystocarps are formed independently of one another, 
as the result of the development, subsequent to fertilisation 
of their own procarpia. 
