XXVI 
INTRODUCTION. 
and loss of individuality results in the formation of a small 
plasmodinm, which in some unknown way possesses the power 
of attracting surrounding free swarm-cells ; these at once 
coalesce, and add to the bulk of the plasmodium. The nuclei 
of the component swarm-cells retain their individuality in the 
plasmodium, the latter retaining the power of motion originally 
possessed by its components, and represents the vegetative phase 
of a Myxogaster.* 
“ At the close of the vegetable period the passage of the 
motile plasmodium into the stationary reproductive condition 
is abrupt, and takes place as follows : — The surface of the 
plasmodium becomes elevated into one or usually many pro- 
tuberances. The original investment of the plasmodium is 
continuous over these protuberances, into which the whole of 
the protoplasm passes, leaving behind the remainder of its 
pellicle attached to the substratum, and known as the fiypo- 
thallus. When these protuberances, which may be sessile or 
stipitate, are symmetrical, and individually distinct, they are 
called sporangia ; when sporangia are irregular in form, usually 
vein-like and creeping, the term plasmodiocarp is used ; finally, 
when the sporangia are densely aggregated, so that their in- 
dividuality disappears to a greater or less extent, an sethalium 
is produced. The three conditions aro connected by inter- 
mediate links.” 
Having assumed some one of these forms, the contents of the 
sporangia gradually become dry and powdery, and consist of 
mostly globose or subglobose spores, mixed with delicate 
threads, often forming a network, and known as the cavil- 
litium. This capillitium may originate from a central colu- 
mella, or from the base of the sporangium, and, when not 
forming a network, radiates from the centre to the periphery. 
By rupture of the walls of the sporangia the spores are dis- 
persed. 
The classification of these organisms, which has been adopted 
in the present work, recognizes five orders, and several sub- 
orders, as follows : — 
Wall of sporangium not encrusted with lime. 
Capillitiutn absent or formed from wall 
of the sporangium ...... Pkiutuichacea:. 
Wall of sporangium not perforated . Tubulin a. 
Wall of sporangium perforated . . Cribrarice. 
Capillitium originating from a central 
columella . ColumellifeejE. 
Springing from every part of the 
elongated columella Stemonilea. 
Springing from the apical portion 
only Lamprodermeoe. 
Capillitium not springing from a colu- 
mella Calotkichacf„e. 
* Massee, “ Monograph of the Myxogasters,” p. 5, 1892. 
