84 SUMMARY OF CUEEENT EESEARCHE8 RELATING TO 



zygospores in the ordinary receptacles. Very different is the origin 

 of the receptacle in five other species of Pilobolus, in which only a 

 single short tuberous jnece is divided off from the mycelium by a 

 sei^tum, the receptacle being produced entirely in this. The energy 

 of the process by which the spores are thrown out is in inverse pro- 

 portion to the length of the pedicel. The author was unable to find 

 zygospores in these species, and believes the sexual mode of repro- 

 duction to have fallen, with them, partially into abeyance. The 

 production of the receptacle of Pilobolus is gi'eatly dependent on 

 light. 



Descriptions follow of other Zygomycetes, Sporodinia grandis and 

 Mortierella Bostajinskii, the latter of which is found on horse-dung. 

 The short mucor-like receptacles are formed on short stolons, and are 

 usually fixed to the substratum by thick bundles of rhizoids at the 

 base of the receptacle, often enveloping it, and thus forming a tissue 

 comj^osed of unseptated filaments, resembling a capsule, and about 

 one-fourth the height of the receptacle, the sporangium being exserted 

 from its apex. The outer portions of this structure are of a yellowish 

 or brownish colour, and are cuticularized, the sporangia remaining 

 white even when mature. The sporangia are not produced from the 

 entire apex of the fertile hyphfe, but only from a small central zone, a 

 jieculiar constriction being formed beneath them. When the spores 

 have been formed out of the protoplasm, a division-wall separates the 

 sporangium from the pedicel without the formation of a columella. 

 As the spores are developing, the walls of the upper part of the 

 pedicel become thicker, as also does the basal part of the wall of the 

 sporangium, which remains behind like a collar when the upjDcr part 

 has become separated and the sjwres have escaped. In old cultures, 

 or those which have been disturbed, gemmpe often made their appear- 

 ance, as in Mitcor racemosus. In very jjoor nutrient fluids, the number 

 of spores was reduced from many thousands to two or four, and the 

 rhizoids were entirely wanting. After long-continued culture, and 

 the succession of from ten to twelve generations, the production of 

 non-sexual recejitacles almost entirely ceased, and zygospores only 

 were produced, enclosed in large brown capsular tissues. In other 

 instances, however, this envelope was wanting. 



The nature of the sporangium and the conidia derived from it are 

 used by Brefeld as the foundation of the classification of the Zygo- 

 mycetes, which he divides into five families, viz. Mucorineae, 

 Thamnidieae, Choanephorete, Chtetocladiacefe, and Piptocephalideae. 



In EntomojjMhora radicans, Brefeld describes the formation of the 

 resting-spores, from which he concludes that the Entomophthoreaj 

 form a small family more nearly allied to the Ustilaginefe than to the 

 Peronosporefe, being most nearly connected with the former through 

 Entyloma. In both families he considers the resting-spores to be 

 oogonia, in which the formation of spores is suppressed, and the 

 oogonium itself has become a spore. Their natural position is 

 therefore in the Oomycetes, near to the Phycomycetes. Two new 

 species of Empusa are described, one parasitic on flies, the other on 

 gnats. 



