r Transactions. 3 
with continued formation of sporangia, a character which is certainly a 
specialized one. It is noteworthy that this character is strongly developed ` 
in Н. multifidum, and not infrequently also in H. minimum, but to a small ` 
degree in T. reniforme. It is completely absent in T. Lyallii, a species which 
is regarded as intermediate between Hymenophyllum and Trichomanes, and 
whose prothallus, it may be added, is of the strap-shaped form characteristic 
of the former genus. 
The prothalli of Т 
in Trichomanes than in Hymenophyllum. : 
it remains to be seen whether or not the facts concerning the New 
Zealand species brought forward in this paper throw any further light 
upon this subject. zx 
It has been shown that the multi-layered condition of the frond-lamina 
in H. dilatatum, H. scabrum, and T. reniforme is developed secondarily 
proceeded, hand in hand with certain other features in specialization, further _ 
of the marginal me This s to suggest that the possess! 
this character must not necessarily be adduced in favour of 
these species as the most primitive the fa Ho 
