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results of analysis. Notwithstanding the Fucus-like aspect and maritime 
habitat of Lichina, there is no longer any question, with lichenists, of its 
place; and one or other of its species has always been associated with 
Lichens. It should seem almost as difficult to recognize any other affinity 
in Ephebe solida, as in Synalissa symphorea. And though Ephebe pubes- 
cens, Fr. (Scytonema dein Stigonema atrovirens, Ag.) offers difficulties in 
its ill-developed fructification, and was regarded by phycologists as — 
from their point of view — closely resembling Scytonema ocellatum, Harv., 
IT suppose few would deny that the former is more lichenose than the 
latter (Herb. Grev.) and fairly enough suggests the long-accepted com- 
parison with forms of Alectoria jubata, and with Parmelia lanata, under 
which (in his Cornicularia) it was grouped by Acharius. The two 
remaining are reduced types, receding from the tribe, as in other instances 
of the present and immediately preceding families, in their pseudo-biato- 
rine fructification; but the more important structural characters of one 
of them (Spilonema, Born., Nyl. Syn. 1, p. 89) confirm its external 
resemblance to Ephebe, and the slenderer thallus of the other (Thermutis, 
Fr. Gonionema, Nyl. l.c. Stigonema pannosum, Hepp Abbild. n. 713) 
offers, it should seem, but little to distinguish it. 
The structural extreme indicated by the younger portions of the thal- 
lus of Ephebe, &c., an extreme especially emphasized by Nylander in his 
character of Thermutis (Gonionema, Nyl. 1. c.) tends however, from the 
first, to modification indicative of greater complexity ; and the constitu- 
ents of the axial column to pass (as Harvey suggested in noting the rela- 
tion of Scytonema to Stigonema, and Flotow in comparing Thermutis and 
Ephebe) into transverse series of collogonidia; a type primarily illus- 
trated by Spilonema, Born. We are next carried a step further by the 
mature structure of Hphebe, Fr., wherein a medullary centre is repre- 
sented by more elongated cells, and a true gonimous layer is even sug- 
gested. And the latter becomes finally distinct, and the whole lichenose 
thallus tolerably evident in Lichina, Ag. 
It is this greater regularity of the gonidial system, first observed in 
Lichina by Tulasne (1. supra cit. & t. 9) and instructively exhibited both 
in this genus and Ephebe, as compared with his Pterygiwm, by Nylander 
(Syn. p. 90, t. 2) which distinguishing, and in the obvious direction of 
higher systematic ‘position, the group before us from the Eucollemet, 
mediates as well between the strongly marked divergence of the latter, 
and the more regular exhibition of Parmeliaceous structure in the family 
here immediately preceding (Pannariet). Nor can such estimate be 
readily questioned, if we follow the learned lichenographer last cited in 
regarding Pterygium, notwithstanding its manifest discrepancies, all 
looking towards Pannaria, as still structurally associable with Lichina; 
whether the former be taken for Collemaceous or Pannariine. The point 
turns on the above alleged indications of structure, and if these are cor- 
rectly understood, Lichina should be comparable with Umbilicaria!; and 
