A Monograj^h of the Myxogastres. 



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between respective orders, and the names in italics to the riglit 

 and left indicate tliose genera that illustrate the maximum 

 of development characteristic of the orders to which they are 

 respectively attached. 



((^latliroptj^cliimiiA 

 Pericliaena. / 



Trie! hi a. 



.Calotkicheae . 



Arcyria. 



i 



In each order we find the special characteristic idea evolving 

 through a sequence of genera, the terminal one not connecting 

 with any higher order, hence the special feature terminates 

 abruptly within the order where it originated, and it is invari- 

 ably in some comparatively undifferentiated genus near the 

 initial point of each order that we meet with the suggestion of 

 a new line of evolution, which at its maximum of development, 

 constitutes the characteristic feature of the order immediately 



