ZYGOMYCETES 117 



are more marked in several respects. In the higher Mucoraceae, Mortier- 

 ella, each single zygospore is surrounded by a sheath; in Endogone, 

 numerous sheathed zygospores come together into a fructification with a 

 common ground tissue, thus forming a sporocarp, according to Brefeld's 

 terminology. In Sclerocystis and Glaziella this fructification shows 

 considerable differentiation. The Mucoraceae, however, are at least 

 morphologically slightly heterogamous, e.g., Zygorhynchus, but dynami- 

 cally still isogamous; some species of Endogone are both morphologically 

 and dynamically heterogamous. Thus in the Mucoraceae which have 

 been investigated, the sexual act and fertilization directly follow each 

 other and the gametangia (except Sijncephalis and its relatives) themselves 

 change to zygospores; in Endogone, fertilization is retarded and a dicaryo- 

 phase, during which the fertilized female gametangium develops into a sac 

 which subsequently becomes a zygospore, is inserted between plasmog- 

 amy and caryogamy. This life cycle may be represented as follows: 



^- : + Sporangium*— ± Mycelium 



1 



*± Sporangium — *• + Spores PC R 



±Sporangiospore— ♦ ± Mycelium ^*+ Gametangium — ►-fCoenogamete j Zygospore— »• 



^—Gametangium — »•— Coenogamete [ 



Diagram XII. 



This scheme corresponds entirely to that of Sporodinia grandis (p. 112), 

 except the formation of the dicaryon, caryogamy and the development of 

 the zygospore is removed one step. 



Entomophthoraceae. — This family is mostly parasitic on insects, 

 higher fungi, fern prothalli, etc., rarely saprophytic on orchid seeds and 

 amphibian dung. The thallus is variable, ranging from a well-developed 

 mycelium of the Basidioboleae to the hyphal bodies of the parasitic 

 Entomophthoreae. The sexual reproduction shows a progressive 

 development from the stage represented by Basidiobolus where a sporan- 

 gium, still capable of developing sporangiospores, is discharged, as in 

 Pilobolus of the Mucoraceae, to the typical conidium of the higher 

 Mucoraceae which germinates by a germ tube. 



The sexual act takes place, as in the Mucoraceae, between coenocytic 

 gametangia, which tend strongly toward heterogamy. The family may 

 be divided into two tribes on the structure of the sexual organs and 

 mycelium : the Basidioboleae with usually uninucleate mycelium and the 

 Entomophthoreae with multinucleate mycelium. In the former, the 

 zygospore membrane is formed as a new structure such as we find in 

 the Ancylistaceae, rather than the usual type of the Zygomycetes. 



Basidioboleae. — At present only two species are known in this group, 

 Basidiobolus ranarum (B. lacertae), saprophytic on the intestinal content 

 and excrement of amphibia (Eidam, 1887; Raciborski, 1896; Fairchild, 



