JOUENAL 



OB' THE 



ROYAL MICROSCOPICAL SOCIETY. 



AUGUST, 1916. 



TRANSACTIONS OF THE SOCIETY. 



XIII. — The Life-history of Mycetozoa, vnth special Reference 



to Ceratiomyxa. 



By GuLiELMA Lister. 



{Bead June 21, 1916.) 

 Plates X, XI. 



The true Mycetozoa — excluding the Sorophora — form a remarkably 

 compact group of tlie class Sarcodina of the Protozoa. The course 

 of the life-history is much the same in all members of the family — 

 the spores give birth to swarm-cells ; these unite and eventually 

 form Plasmodia ; the plasmodium at length concentrates to form 

 aerial reproductive bodies producing spores. The spore-bearing 

 bodies consist usually of membranous cases enclosing spores, and 

 are called sporangia ; in one species, Ceratiomyxa, the stalked 

 spores are borne on the surface of gelatinous processes, the sporo- 

 phores. The former class constitutes the Endosporeee, and contains 

 a]30ut 2(30 species ; Ceratiomyxa is the sole representative of the 

 class Exosporese. 



In the following notes I propose to rehearse briefly the 

 life-history of one of the Endosporese, and then to compare it 

 with that of Ceratiomyxa. As an example of the former class, 

 Badhamia utriculai'is may be chosen. It is an abundant species 



EXPLANATION OF PLATE X. 



Freshly-formed sporophores of Ceratiomyxa fruticulosa, magnified about 

 80 times. From a photograph by J. Howard Mummery. 



Aicg. 16th, 1916 2 c 



