ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 233 



of Aspergillus niger. The conids adapt themselves to the concentration 

 of the fluid in which they are grown more readily in the second genera- 

 tion than in the first. When they have adapted themselves to more 

 highly concentrated solutions, they lose the capacity of thriving as well 

 in those of lower concentration. Culture in a normal solution for a single 

 generation does not destroy the influence of growth for one or two 

 generations in moi'e concentrated solutions. 



Cell-membrane of the Mucorineae. * — From a careful study of the 

 structure of the cell-wall in representatives of different families of the 

 Mucorineae, M. L. Mangin st ites that it presents special characters which 

 distinguish the members of this order from the other Oomycetes. While 

 in the Peronosporeae and Saprolegnieae the membrane is partly formed 

 of callose, this fundamental substance, characteristic of the mycele of 

 a large number of Fungi, is usually wanting in the Mucorineae. Both 

 the aerial and the submerged mycele, as well as the sporiferous filaments, 

 consist of cellulose associated with pectic compouu Is, and, as in flowering 

 plants, the cellulose is in a larger proportion in the inner than in the 

 outer layers of the cell-wall. The cellulose is more resistant to chemical 

 agents (Schweizer's reagent) than that of Phanerogams and Vascular 

 Cryptogams. In a large number of species, especially in the MucoreaB, 

 Piloboleae, and Mortierellese, the outer membrane of the sporiferous 

 filaments is covered by a mineral incrustation. This coating is entirely 

 wanting in the Syncephalideae. 



In those species which have a deliquescent sporange, its membrane 

 presents a special structure. Before the spores are formed, it becomes 

 double from a thick internal layer composed of callose. As this layer 

 thickens, the outer membrane becomes mineralised aud the cellulose 

 disappears ; finally the mineral coating is in immediate contact with the 

 layer of callose which forms the deliquescent part of the membrane. 

 In the Syncephalideae the membrane of the sporange does not deliquesce. 

 The thick membrane of the endogenous spores, spores properly so-called, 

 and chlamydospores, does not respond to the reactions of the membrane 

 of the mycele ; it consists almost entirely of callose. On the other hand, 

 the membrane of the exogenous spores, stylospores, and zygospores, 

 corresponds to that of the mycelial filaments. 



New Pathogenic Mucorinea.| — M. Lucet and M. J. Costantin de- 

 scribe a fungus found in the larynx of a woman, which they name 

 Rhizormicor parasiticus, the type of a new section of the genus Mucor. 

 The mode of branching is that of a Mucor ; but it is distinguished by 

 the presence of rhizoids springing from the creeping mycele resembling 

 those of JRhizopus. It is pathogenic to men and other animals. 



Mortierella van Tieghemi sp. n.J — Herr H. Bachmann describes a 

 new species of this genus, found on horse-dung, allied to M. candelabrum. 

 It is characterised by forming strongly warted stalked conids or stylo- 

 spores, in addition to sporanges and ordinary conids ; no zygospores 

 were seen. The results of culture under various conditions and oa 

 various nutrient media are given in detail ; the presence of nitrogen in 



* Journ. de Bot. (Morot), xiii. (ISO!)) pp. 209-16, 276-87, 307-16, 339-4S, 471-8 

 (2 pis. ami 7 tigs.). t Comptes Kendus, exxix. (1899) pp. 1031-4. 



X Pringsheiui's Jahrb. f. wiss. Bot., xxxiv. (1899) pp. 279-328 (2 pis.). 

 April 18th, 1900 r 



