364 
POPULAR SCIENCE REVIEW. 
Discovery of Two New Planetary Nebulce. — In a communication to 
Nature (August 5th, 1880), Prof. Edward 0. Pickering, of the Harvard 
College Observatory, announces the discovery of two very small planetary 
nebulae. The one discovered on July 13th, is in R.A. 18 h 25 m, 2, and Decl. 
— 25° 13' ; and the second, discovered on July 14th, is in R.A. 18 h 4 m- 3, and 
Decl. - 28° 12'. Both are very minute, and can only be distinguished from 
stars of about the tenth magnitude by their spectra. Prof. Pickering points 
out that all attempts which have hitherto been made to determine the 
parallax of a planetary nebula have been foiled by the uncertainty in deter- 
mining the exact centre of these bodies, or by the haziness of their borders, 
but the minuteness of the disc presented by the two newly observed nebulae 
would permit of their places being determined with the same accuracy as a 
star. 
BOTANY. 
Classification of Cryptogamia. — At the recent meeting of the British As- 
sociation, Mr. A. W. Bennett laid before the Biological Section a proposed 
modified classification of the Cryptogamia. He remarked that in Sachs’ most 
recent classification, the Thallophyta (including the Characeae) are divided 
into four classes, namely, Protophyta, Zygosporeae, Oosporeae, and Carpo- 
sporeae. In his proposed classification, Mr. Bennett removes the Characeae 
altogether from the Thallophytes as a distinct group. The Thallophyta are 
then divided into three primary classes, namely, Protophyta, Fungi, and Algae. 
The Protophyta are divisible into two sub-classes, Protomycetes and Proto- 
phycece ; the former including only a single order, the Schizomycetes ; the 
latter consisting of the Protococcaceae (including Palmellaceae and Scy- 
tonemeae), Nostocaceae, Oscillatorieae and Rivularieae. The Myxomycetes 
are treated as a supplement to the Protophyta. 
The Fungi include three sub-classes : the Zygomycetes composed of the 
Mucorini alone ; the Oomycetes, containing the Peronosporeae and Sapro- 
legnieae ; and the Carpomycetes, comprising Uredineae, Ustilagineae, Basidio- 
mycetes, and Ascomycetes, the Lichens being included in the last as a sub- 
order. 
The Algae also form three sub-classes corresponding with those of the 
Fungi, namely, the Zygophycece , including the orders Pandorineae, Hydro- 
dictyeae, Confervaceae, Ulotrichaceae, Ulvaceae, Botrydieae, and Conjugatae 
(under the last of which we have the Desmids, Diatoms, Zygnemaceae, and 
Mesocarpeae) ; the Oophycece, comprising Yolvocineae, Siphoneae, Sphaero- 
phyceae, CEdogoniaceae, Fucaceae, and Phceosporeae ; and the Carpophycece, 
including only the Coleochaeteae and Florideae. 
The Characeae, as already stated, are regarded as forming a distinct 
primary group. The Muscineae are retained in the same sense as by Sachs. 
In the case of the Vascular Cryptogamia, Mr. Bennett proposes to adopt the 
primary distinction into Isosporia and Heterosporia as most in accordance 
with probable genetic affinities. The former include the Filices, Lycopodi- 
aceae and Equisetaceae ; the latter the Rhizocarpeae and Selaginellaceae. — 
Nature , 9th September . 
