ZOOLOGY AND BOTANY, MICROSCOPY, KTC. 669 



Ceramium.* — H. E. Petersen publishes some studies on Geramium, 

 The first consists of remarks on Danish species of Ceramium, viz., 

 C. tenuissimum, G. strictum, G. Areschougii, ('. fruticiilosum, and C. 

 r ubru m. Points of a systematic character are discussed with regard to 

 G. strictum, G. diaphanum, and < '. fruticulosum, the first two of which 

 are not easily distinguished. Information is also given on the refringent 

 cortical cells containing proteid matter which are common in some 

 species, and on the development of main axes in G. rubrum, C. fruti- 

 culosum, and C. diaphanum. The second study is devoted to researches 

 on Geramium species from the Faeroes, Iceland and Greenland. The 

 distribution of the species in the three areas and Denmark is shown in 

 tabular form. Three new species are described. Six types are recognized 

 for the many forms of G. rubrum. 



Lithothamnia from Roscoff in Brittany. f — F. Heydrich writes on 

 certain species of Lithothamnia collected in the neighbourhood of Roscoff 

 by Chalon. Among these are specimens of Foslie's L. Battersii (?), 

 sunk by the author into Phymatolithon polymorphum Fosl. Lithotham- 

 nion rubrum Phil, is given a new diagnosis and divided into five new 

 forms. A new form is described for L. calcareum Aresch., and a new 

 genus is created to contain Melobesia Lenormandi Aresch. under the 

 name of Squamolithon. 



Tolypella intricata Leonh.J — Gr. C. Druce writes a note recording 

 the reappearance of Tolypella intricata in the ditches at Marston, Oxford, 

 for the fourth time. The ditches in question had been cleared in each 

 case the previous autumn. 



Fungi. 

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



Aphanomyces lsevis.§ — By careful research V. Kasanowsky has 

 proved fertilization in this genus of Saprolegniaceas. The species ex- 

 amined was collected, along with other fungi, on a dead fly in a pool 

 near to Kiews ; it was isolated and successfully cultivated. A detailed 

 account is given of the methods employed in fixing, staining, etc. 



Aphanomyces Isevis is monoecious, and from a mycelium produced 

 from a zoospore developed oogonia and antheridia, the former full of 

 plasma, and with a large number of nuclei and a large vacuole. As the 

 vacuole enlarges it pushes the contents towards the periphery and many 

 of the nuclei degenerate ; those that remain divide once, but all 

 degenerate except one, which becomes the egg-nucleus. The egg is 

 formed by protoplasm gathering towards the centre with a ccenocentrum 

 in the middle, of which the function is to form a centre of nutrition. 

 The nucleus lies near to the ccenocentrum and increases in size. 



The antheridia are at first multinucleate, but they all degenerate 



* Bot. Tidsskr., xxxi. (1911) pp. 97-120 (5 pis.). 



t Ber. Deutsch.Bot. Gesell., xxix. (1911) pp. 26-33 (lpl.). 



§ Journ. of Bot., xlix. (1911) pp. 235-6. 



§ Ber. Deutsch. Bot. Gesell., xxix. (1911) pp. 210-28 (1 pi.). 



Oct. 18th, 1911 2 x 



