ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 
309 
angle with the surface of the frustule. These threads are also invisible 
in clear water. In other species of Pinnularia , e.g. P. oblonga , and in 
the genera Navicula , Pleurosigma , and Nitzschia, both the gelatinous 
envelope and these granular projections appear to be wanting. 
Schmidt’s Atlas der Diatomaceen-Kunde. — Heft 54 contains plates 
213—216, and includes species of the genera Bhoiocosphenia , Gomphonema , 
and Didymosplienia (a new sub-genus of Gomphonema, distinguished by 
the end of the raphe being always clearly distinguishable in the two 
terminal nodes). The illustrations are marked by the usual clearness 
and accuracy of detail. Dr. Martin Schmidt succeeds his father as 
compiler of the Atlas. 
Fungi. 
Respiration of Fungi in different Nutrient Solutions.* — From ex- 
periments made by Herr K. Puriewitsch on the growth of Penicillium 
glaucum in various solutions, he derives the general law that the value 
CO 
of the proportion — increases with the concentration of the solution up 
0 2 
to a certain optimum, and beyond that decreases. For dextrose and 
saccharose the optimum concentration is about 10 per cent. With 
tartaric acid the concentration appears to have no effect on the pro- 
portion. With water containing only a very small quantity of mineral 
salts, the fraction is much below unity. 
Influence of Light on the Respiration of the Lower Fungi.f — A 
series of culture experiments on a variety of Fungi and Schizomycetes 
has led Herr R. Eolkwitz to the following general conclusions : — Light 
promotes the process of respiration, independently of the morphological , 
conditions of the culture and of the nutrient substance. This is in direct 
opposition to previous results. Intense sunlight, or electric (arc) light, 
has a deleterious and even fatal effect on many bacteria. 
Dangeardia, a New Genus of Chytridiacese.j: — Herr B. Schroder has 
found, on Pandorina morum , a parasitic fungus, which he makes the type 
of a new genus under the name Dangeardia mamillata g. et sp. n. The 
following is the diagnosis of the genus : — Intramatrical mycele un- 
branched, short, brush-like ; sporange solitary, sessile, with smooth 
membrane, flask-shaped before maturity, 30 p, long by 16-20 /x broad, 
opening by an orifice at the apex ; swarm-spores ovoid or ellipsoidal, 
about 2*5 p. broad, 3*4 /x long, with refringent oil-drops, and a single 
cilium 3-4 times as long ; resting spores intramatrical, ellipsoidal, with 
thick papillose or spiny membrane and large excentric oil-drops, 13 • 6 /x 
long by 10*2 /x broad. 
The fungus is parasitic on the spherical cells resulting from the non- 
sexual multiplication of Pandorina morum. The author places it, along 
with Chytridium and Polyphagus , in the order Monochytridineae, family 
Sporochytriaceae, sub-family Orthosporese. 
Herr Schroder gives also a detailed description of the mode of non- 
sexual multiplication of Pandorina morum. 
* Ber. Deutsch. Bot. Ges., xvi. (1S9S) pp. 290-3 (1 tig.). 
V Jahrb. f. wiss. Bot. (Priugskeim), xxxiii. (1898) pp. 128-70 (2 pis.). 
X Ber. Deutsch. Bot. Ges., xvi. (1898) pp. 314-21 (1 pi. and 1 tig.). 
