ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 463 



white. He has added three new species to the genus Dictyostelium: 

 D. brevicaule, which has a persistently short stalk and a large sorus, and 

 D. purpureum aud D. aureum, which are distinguished hy their bright 

 coloration. Polysphondylium pallidum and P. album are also additions 

 to the llora of the Acrasieae. Only one member had been reported from 

 America before Mr. Olive began his study of the group. The paper is 

 a contribution from the Cryptogamic Laboratory of Harvard University. 



Genus Mucor.* — W. Schostakowitsch has added seven new species 

 to the genus Mucor from the neighbourhood of Irkutsk. M. proliferus, 

 which is very common round Irkutsk, has two kinds of sporangia ; one 

 large and strongly incrusted, which terminates the main hyphae ; the 

 other, smaller and smooth, is borne at the tops of the branches. In old 

 cultures one or more processes grow out of the columella and develop 

 a branched mycelium, which bears the smaller type of sporangium, 

 M. irkutensis has but one type of sporangium, which is globose, and 

 attains to the large size of 1 mm. in diameter. The spores are also 

 rather large, 28 /x by 10" 5 /a. M. cinereus has somewhat grey globose 

 sporangia on strong stalks 30-40 /x in width and 1-4 cm. long. M. 

 agglomerates is characterised by a racemose branching of the ordinary 

 type, and further by cushion-like swellings on the main stem and 

 branches, from which arise a number of sporangiophores (5-20) bearing 

 very small sporangia. In M. angarensis the hyphae are much branched 

 and circinate at the tops. The sporangia are globose and black. The 

 columella and spores when massed are slate-blue in colour. M. de 

 Baryanus forms dark coloured masses. .After ripening, the sporangia 

 bend down towards the substratum and form from the stalk beneath 

 the columella a series of outgrowths which grow into a branching 

 mycelium and give rise to new sporangiophores. Gemmae are abundant 

 as in M. racemosus. M. heterosporus sibiricus becomes brown when mature. 

 The hyphae are richly branched, the sporangia globose and rather small. 

 Gemmae are produced in great numbers on the hyphae. In none of the 

 species have zygospores been observed. 



The same author "j* has described a new species of Mucor from 

 Siberia. It was found growing on cooked rice. The sporangiophores 

 are usually unbranched, and reach a height of 10-12 cm. ; the sporangia 

 are 0*5 mm. in diameter. In old cultures, the sporangiophores that have 

 remained sterile swell out near the tops, and from this portion arise a 

 series of unbranched sporangiophores with somewhat smaller sporangia. 

 These and other peculiarities serve to differentiate this species. 



He also describes the changes induced in Mucor proliferus by 

 bacteria. So great was the influence of the bacteria on the form of 

 the Mucor that another species seemed to have been formed. The 

 sporangiophores were differently branched and prostrate, the sporangia 

 much smaller, most of them sessile and without spores, the columella 

 from conical or pear-shaped had become globose, the spores more round 

 in shape and olive-green instead of colourless. 



Parasitic Fungi of the Diatomaceae.J — Under the general title 

 Archimyceten Marpmann has described the one-celled fungi that infest 



* Zeitschr. f. angew. Mikr., vii. (1902) pp. 311-5. 



t Op. cit., viii. (1902) pp. 5-10. \ Tom. cit. pp. 1-5 (1 pi.). 



