152 THE NORTH AMERICAN SLIME-MOULDS 



original collections of M. Roze, which, it appears, are no longer 

 to be consulted. Under these circumstances, Wingate's refer- 

 ence cannot be verified, and our species becomes E. splendens. 

 New England, Canada, to Minnesota and Nebraska, South 

 Dakota. 



3. Dictydiasthalium Rostafinski. 



1873. Dictydiathalinm Rost., Versttch, p. 5. 

 1875. Clathroptyckium Rost., M(w., p. 224. 



./Ethalium depressed, flat ; the sporangia erect, regular, pris- 

 matic by mutual pressure, the peridia convex above, wanting at 

 the sides, and within the asthalium represented by vertical 

 threads marking the angles and passing from base to summit. 



This genus is readily recognized by the internal structure of 

 the sethalium. The lateral wall-openings, which, as we have 

 seen, characterize the sporangia of the preceding genus, here 

 become extreme, occupying to such extent the lateral wall-space 

 of each sporangium that only slender threads remain to mark 

 the vertical angles. 



In 1873 Rostafinski applied the generic name here adopted, 

 because he thought he discovered close relationships with Dic- 

 tydium. In 1875, believing his first impressions erroneous, and 

 desirous that the nomenclature might not at once mislead the 

 student and perpetuate the memory of his own mistake, the 

 same author proposed the name by which the genus has gener- 

 ally ever since been known ClatliroptycJiium. However sen- 

 sible the later conclusion reached by our Polish author, it is 

 plainly contrary to all rules of priority. 



Our region shows but a single widely distributed species, 



I. DlCTYDI.ETHALIUM PLUMBEUM (St/tUMl.) Rost. 



PLATE I., Figs. 2, 2 a, 2b. 



1803. Fuligo plumbea Schum., Fl. Sail., No. 1410. 



1833. Licea rugulosa Wallroth, Cr. Fl. Ger., IV., p. 345. 



1873. DictydicEthalinm plnmbenm (Schum.), Rost. Versuch, p. 5. 



1875. Clathroptychiwn rngnlositin (Wallr.) Rost., Mon., p. 225. 



1894. Dictydiathalium plumbeum Rost., Lister, Mycetosoa, p. 157. 



