ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 355- 



unpaired. The fused nuclei increase to a large size, and on division the 

 daughter nuclei possess eight double chromosomes ; these become the 

 spore-nuclei. Jahn considers this process as homologous with the hetero- 

 typic division in the " gonotokonten " cells of Metaphytes and Metazoa, 

 though the nuclei are too minute for detailed observations. The spore 

 goes into restino- condition and the first division of the nucleus of the 

 amoeba or zoospore which issues from the spore should be a reductionj 

 division. Jahn thinks he has proof of this : the daughter-nuclei show 

 four chromosomes (double-chromosomes) the reduced number. In 

 Myxomycetes we thus find the reduction process during the resting 

 stage. In the protophytes, especially in fungi, spore-formation follows 

 immediately on karyogamy. Jahn then describes the stages that occur 

 in Geratiomyxa, a primitive mycetozoon. They are different, inasmuch 

 as there is karyogamy in the early stage, then karyokinesis, before spore- 

 formation, which is a reduction division. The spore nucleus increases 

 in size and divides twice, forming four nuclei ; these divide again on 

 germination. 



Grass-killing Slime Mould.* — J. W. Harshberger notes the instance 

 ■of parasitic slime moulds, Flasmodiophora hrasskm, which attacks cruci- 

 ferous plants, and Dendrophwjus globularis, which enters the stems of 

 young cherry, plum, peach, and apricot trees. He then goes on to de- 

 scribe a disease that had attacked the grass on a lawn, large patches 

 being blackened and the blades of grass destroyed. On examination he 

 found this was due to the presence of Physarum cinereum. The author 

 does not describe the kind of injury inflicted, whether it was only a 

 smothering of the grass or a feeding on it. He rather implies the latter, 

 as he says the plasmodium had left its saprophytic habit and assumed a 

 grass-killing one. The roots of the grass were uninjured, and the leaves 

 grew again very quickly. 



ScHROEDEB, H. — Ucber den Nachweis einiger Enzyme in dem Fruchtkorper der 

 Lohbliite (Fuligo varians). (Proof of the existence of an enzyme in the fruit- 

 bodies of Fuligo varians.) 



[The author found an enzyme in the fruit-bearing plasmodia of the myce- 

 tozoon.] Beit. Chem. Pliys. Path., 19l;7, p. 153. 



See also Bot. Zeit., Ixv. (1907) pp. 67-8. 



Schizophyta. 

 Schizomycetes. 



Pedioplana Haeckeli and Planosarcina Schaudinni.f — M. Wolff 

 describes two new motile members of the Coccacese. (a) Pedioplana 

 Haeckeli forms motile colonies on rotten turnips ; the colonies are more 

 or less rectangular plates and are moved by very long flagella (27/i., or 

 fifty times the diameter of the coccus) ; the motility becomes more active 

 on increasing the alkalinity and on warming to 30° C. The size of the 

 individual cocci diminishes with the generation ; they are separated in 

 the colonies by refractile lines of intercellular matter, which increases 

 with the generation to twice the breadth of the coccus. The organism 



* Proc. Amer. Phil. Soc, xlv. (1906) pp. 271-3. 

 t Centralbl. Bakt., 2te Abt., xviii. (1907) p. 9. 



