LES ALGUES DE P. K. A. SCHOUSBOE. — LES LICHENS. 59 
Les Alques de P. K. A. Schousboe. Par Eipovanp Borner (Masson, 
Paris, 1892). Extr. des Mem. de la Soc . Nat. 
et Math. de Cherbourg, t. xxviii. i, pp- 216, 3 tab. 
wth of Alge will cordially welcome this volume by M. 
Bornet, giving an account of the Algw collected in Morocco and 
the Mediterranean (1815-1829) by Peter cdasaben, who was 
Danish Consul at Morocco for some thirty years. Those who 
possess the valuable sets of Alg@ Schousboeane will be especially 
glad of this ers work. It is prefaced by a very suggestive, brief 
essay on the affinities of the marine flora of this region; but the 
feature of vantigull value is contained in the notes on the species. 
Their critical value is beyond estimation in this short note. It is 
scarcely necessary to add that the = are illustrations 
of the kind one sees only too seldom 
Les Lichens: Etude sur srsmegee la physiologie et la morphologie 
de Vorganisme lichénique. Par A. Actoqur. Paris: Bailliére 
et fils. 1893. Pp. viii. "876, fig. 82. 3 fr. 50. 
Turs is one of the last lavage to the Bibliothéque Scientifique 
e hundred volumes 
Contemporaine, - which s have already 
appeared. The e is Sern gine clear, ‘ed comm andabiy free 
from misprints. ‘the illustrations are woodcuts intercalated in the 
letterpress. While ce cueee of the way in which the publishers 
have got the book up, we feel it our duty to express our dis- 
satisfaction with them for datihe the title-page ‘ 1893,” since the 
b 
Up 
eae barca rion nostoch n’est pas un lichen seca et 
possibility of its being anything an alga, we determined - 
search for further particulars. The rier of our search is that w 
find M. Acloque to be disinclined to entertain the theory of sedan 
dener and the « hétérogonidistes,” who hold that a seegevt is a 
and 
Suffice it to say that in M. Acloque’s opinion the two elements of a 
lichen develop themselves separately at first, giving rise to distinct 
eres imperfect so long as they remain isolated. Nostoc is an 
ance of the purely gonidial state, capable of indefinite growth 
as Noss c, but incapable of generating hyphe and of becoming a 
completely developed lichen. It must wait, as it were, until som 
matrimonially inclined hypha or spore comes along and offers to set 
up someon sara with it; and then things just hum around, as the 
