ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 481 



with a sponge. They both come from the East Indian Archipelago, and 

 entirely dispel the doubt cast by Oltmanns (Morph. u. Biol, der Algen II., 

 p. 373), that genuine cases of such symbiosis exist. The author describes 

 the structure of the two species, and finds that they both possess chains 

 of moniliform cells, hitherto unknown for Thamnoclonium. These cells 

 she describes in detail, and sets forth the various points of interest in 

 connexion with them. On the ground of possessing these peculiar 

 chains of cells, she separates the two new species from the rest of the 

 genus, placing them in a section Neniatophorae, the other species being 

 Anematophorae. Between the two sections there exists also an ana- 

 tomical difference, which is described. 



Fossil Algae.* — L. Cayeux has made a study of the calcareous algae 

 of the Girvanella group, and of the oolites in which they are found. In 

 this short note he summarises briefly the views of other authors, and 

 then describes his own conclusions. He proves that the Girvanella are 

 in reality a group of perforating algae, which inhabit the ooHtes in the 

 manner of parasites ; and that the concentric structures in the host-bodies 

 have no connexion with the invading alga, but belong to the oolitic 

 mass. The views of Wethered are not in accordance with those of the 

 author of this paper, and they are shown to be incorrect. 



Fungi. 

 (By A. Lorrain Smith, P.L.S.) 



New Genus of Chytridineae.f — R. F. Griggs found the new fungus 

 on the leaf -blades and petioles of the ragweed {Ambrosia artemisiifolia). 

 The swarm-spores perforate the cells, and enter the tissue of the plant 

 in great numbers as amoeboid forms. They unite in pairs, the nuclei 

 remaining distinct, and finally the fused amoebae become a binucleate 

 resting-spore with a stout exospore wall. Germination has not been 

 studied. Other swarm-spores grow to form zoosporangia, the first 

 nucleus being said to fragment into four nuclei at an early stage ; 

 finally, after successive divisions, minute zoospores are formed. The 

 escape of the zoospores was not observed, and the author is not certain 

 if they are ciliate or amoeboid, but probably they are amoeboid. He 

 calls the fungus Monochytrium Stevensianum g. et sp. n. Though the 

 infected cells increase in size, very little deformity of the host-plant 

 takes place. 



Phytophthora infestans.J — D. McAlpine has devoted considerable 

 attention to this destructive fungus. He sums up in a series of state- 

 ments the results of his investigations : that only seed potatoes free 

 from disease should be used, and that these should be carried in new 

 bags ; that as tomatoes are also liable to the disease, they should not be 

 grown on infected areas ; that the fungus in suitable conditions develops 

 very rapidly, but may be checked and killed by spraying with Bordeaux 

 mixture, or the tubers may be rendered superficially clean by dipping 

 in formalin. He gives special notes on the action of heat and moisture 



* Comptes Rendus, cl. (1910) pp. 359-62. 



t Ohio Nat., x. (1910) pp. 44-54 (2 pis.). See also Bot. Gaz., xlix. (1910) pp. 

 311-12. % Ann. Mycol., viii. (1910) pp. 15G-6G (1 pi.). 



Aug. 17th, 1910 2 K 



