242 Dr. A. de Bary on the Mycetozoa. 



in all essential points with the Amoebiform beings which origi- 

 nate from the spores of Mycetozoa ; further, a certain number 

 of Amoebae (e. g. A. radiosa, A. verrucosa) occur not only in 

 freshwater ponds, but still oftener in places where Mycetozoa 

 are abundant, as in the moist detritus about fallen leaves and 

 mosses in woods, on decayed wood, and about Fungi, &c. It is 

 moreover to be remembered that the Mycetozoa- spores readily 

 germinate in water (figs. 1, 2, 8), and that in the wide distribu- 

 tion of the Mycetozoa, their many species, their multitudinous 

 spores, the lightness of these, and the facility with which they 

 may be scattered abroad and carried through the air, we have 

 little difficulty in presuming the genetic connexion of the aquatic 

 Amoeba? with them. 



It is supposable that the aquatic Amoebae may by their motile 

 power leave the water for external conditions better adapted to 

 their further development into Mycetozoa ; or that, on the con- 

 trary, they may confine themselves preliminarily to a multipli- 

 cative process, or to encysting, and sink to the bottom when 

 external conditions are unfavourable. 



The foregoing reflections, therefore, render it probable, to say 

 the least, that many aquatic Amoebae are phases of being in the 

 development of Mycetozoa. Others, which from their locality 

 and their form differ very widely from the common type, such, 

 for instance, as Amoeba porrecta (Schultze), or such as A. gut- 

 tula and A. Limax, which are remarkable by the absence of 

 slender pointed pseudopodia, and by their movements, are, in 

 all probability, generative phases of other animals, possibly of 

 the testaceous Rhizopods. This reasoning on possibilities and 

 probabilities needs, however, to be established by observation ; 

 and the author advances the foregoing researches only as guides 

 to future inquirers. 



EXPLANATION OF PLATE VI. 



Fig. 1. Spores of Stemonitis obtusata placed in water : a, one such in which 

 the contained " swarmer " is beginning to escape. Magnified 

 390 diameters. 



Fig. 2. Two spores of the same organism : in b, the swarmer has almost 

 escaped. 



Fig. 3. A stalked spore-holder (Sporenblase) of Physarum albipes, divided 

 longitudinally, and viewed on the cut surface. The dislodg- 

 ment of the contained spores reveals the "columella" and 

 " capillitium." Magn. 390 diams. 



Fig. 4. A group of immature sporothecae of Physarum plumbeum. A few 

 of the sarcode-cords, from which the spore-holders originate, are 

 seen in the form of fibres. 



Fig. 5. " S warmers," a to f, in various stages of self-fission. The vacuoles 

 are seen in a state of diastole (expansion) in |3, , and ; but are 

 invisible in y and e, owing to their condition of systole or con- 

 traction. Magn. 390 diams. 



