MORPHOLOGY AND TAXONOMY OF THE SARCODINA 447 



Liberation of the spores is accomplished in different ways. In 

 some cases a lid is raised off the sporangium; in others the peridinm 

 dissolves in spots leaving a fenestrated capsule; in still others the 

 capsule splits longitudinally. The dry, powdery spores are distrib- 

 uted in various ways, air currents playing a conspicuous part, and 

 they finally germinate in the presence of moisture. Myxamebae 

 and myxoflagellates are formed and the cycle is completed. 



Fig. 184. -Fruiting bodies of Comatricha nigra. A, five stalked spore capsules; B, 

 section of capsule with columella, capillitium, and spores. (After MacBride.) 



Genera and species of Mycetozoa are distinguished according to 

 the nature of the plasmodia and by the form and organization of 

 the sporangia. 



Order I. ACRASIDA van Tieghem. 



(Pseudoplasmodidae of Zopf-Delage) Sorophora Lister (in part). 



The individual ameboid organisms after a period of creeping by 

 active ameboid movement come together in clusters to form the 

 pseudoplasmodia, the amebae retaining their individuality. Indi- 

 viduals creep up over their fellows and form groups or sori which 

 in some cases are stalked, the stalks being formed by the dried 

 bodies of sacrificial Amebae. The sori are formed by other amebae 

 creeping over the stalk and accumulating in a mass at the top. Here 

 each encysts and when a suitable medium is assured the small 

 amebae again creep out, often, however, after a long period of 

 desiccation. Their characteristic habitat is animal dung. 



While many competent authorities regard these organisms as 

 remotely related, if at all, to the more complex Mycetozoa, we 

 believe that their affinities are more probably here than with any 

 other group of Protozoa. The three families recognized show 

 different gradations in complexity. 



Family 1. Sappiniidae Dangeard.— The single genus— Sappina 

 Dangeard — shows the characteristics of the family which differs 



