ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 339 



Fungi. 



Cytology of Araiospora pulchra.* — C. A. King gives an historical 

 resume of the species of Araiospora, with a more particular description 

 of A. pulchra. The main part of the work is devoted to the account 

 of the development of the sexual organs of this species. The oogonia 

 arise singly or in umbels at the distal ends of certain segments, which in 

 turn produce special segments on which the antheridia are borne. The 

 oogonium contains thirty-five to fifty-five nuclei, which migrate to the 

 periphery, where cells are formed each with one or more nuclei. The 

 further changes in the protoplasmic structure are followed in detail ; 

 when mature there is a deeply staining fine-meshed mass of protoplasm 

 in the centre, and one nucleus. No antheridial tube is formed. The 

 passage between the two organs is oogonial in structure. After the 

 male nucleus has entered the oosphere, the central mass radiates out 

 into the peripheral ooplasm. The two nuclei put out beaks toward 

 each other, which in some cases come in contact. The nuclei may 

 remain pointed until the oospore wall is partly formed. The later 

 stages of fertilisation were not seen ; fusion probably takes place at a 

 later stage. King concludes from his studies that Araiospora should 

 be placed between Pythium and the Saprolegniaceas. 



Peronosporese.j — A monograph of these fungi was prepared by 

 A. X. Berlese before his death, and has now been issued. He divides 

 the species of Peronospora into three groups distinguished by the 

 form of the branchlets of the conidiophores. A short historical account 

 of the genus is given, and full descriptions of each species. The rnono- 

 typic genus Bremia is also included in the monograph ; and a biblio- 

 graphy of the literature on the subject is given, with an index of the 

 species. 



Spinellus chalybeus and the Spinellus Group.} — Paul Yuillemin 

 has found that a fungus growing on a decaying agaric is identical with 

 a species described in 1845 as Ascophora chdlybm, and which has not 

 been encountered since that date. It is characterised by the aerial fila- 

 ments which gradually become brown, by the swollen base of the 

 sporangiophore and the dilated apophysis, and by the evanescent wall 

 of the sporangium. Yuillemin finds that the spinous mycelium which 

 gave the name to the genus is not a generic character. He connects 

 the three genera Spinellus, Dicranophora and Sporodinia closely together ; 

 they form ^jjlujlum in the genealogical sense. 



Sexual Reproduction of Basidiobolus.§ — Z. Woycicki has rein- 

 vestigated the development of the zygospore in B. ranarum. He finds 

 that the nuclei which enter the zygospore do not fuse directly, but each 

 undergoes an amitotic division. Two of the four nuclei so produced 

 become disorganised, while the other two fuse in course of time to form 

 the single nucleus of the zygospore. He compares this with the process 



* Pruc. Bost. Soc.Nat. Hist., xxxi. (1903) pp. 211-45 (5 pie.). 



t Kevista Patol. Ve*., x. (1904) pp. 1S5-29S (69 figs.;. 



% Ann. Mycol., ii. (1904) pp. 01-69 (1 pi.). 



$ Flora, xciii. (1904) pp. b7-97 (1 pi.). 



