The white crust-like outer wall has more than once carried this species into _Diderma_. It is still doubtful whether we are here dealing with _Chondrioderma calcareum_ Rost. Miss Lister cites a variety, _S. difforme comatum_, with more abundant capillitium which may represent Rostafinski's species. Evidently rare in the United States; reported more common in Europe and eastward. In our specimens the crust-like outer peridium shows crystals on the broken edge only; the body of the object, as its outer surface seems to be amorphous. 17. DIDYMIUM QUITENSE (_Pat._) _Torr._ 1895. _Chondrioderma quitense_ Pat., _Bull. Soc. Myc. Fr._, XI., p. 212. 1909. _Didymium quitense_ (Pat.) Torr., _Flor. Myxom._, p. 150. 1911. _Didymium quitense_ Torr., List., _Mycetozoa, 2nd ed._, p. 126. 1913. _Didymium quitense_ (Pat.) Torr., Sturg., _Myx._, Col. II., p. 446. Sporangia more or less plasmodiocarpous, scattered, depressed, white; the outer peridium distinct, crust-like, remote from the thin membranous inner wall; columella undefined; capillitium brown, much branched, forming a network especially outwardly; spores very dark violaceous-brown, rough with a tendency to obscure reticulation; 12-14 mu. This species is different from _D. difforme_ chiefly in the rougher and somewhat banded epispore. It is reported from Ecuador by Father Torrend, and from Colorado mountains by Dr. Sturgis to whose kindness I am indebted for the specimens here described. Evidently a high mountain species. Colorado. 18_a_. DIDYMIUM ANOMALUM _Sturg._ PLATE XIX., Figs. 13 and 13 _a_. 1913. _Didymium anomalum_ Sturg. _Myxomycetes of Col._, II., p. 444 Sporangia in the form of very thin effused grey plasmodiocarps, 2-10 cm. long, 1 mm. or less in thickness. Wall single or membranous, hyaline or yellowish, with rather scanty deposits of small, stellately crystalline or amorphous lime. Columella none. Capillitium consisting entirely of straight membranous, tubular, columns, extending from the base to the upper wall of the plasmodiocarp, 7-22 mu thick and usually containing small crystalline masses of lime. Spores bright violet-brown, minutely and irregularly spinulose, 10-11.5 mu diam. Hab. on the inner bark of Populus. Colorado Springs, Colo., July 1911. Our specimens by the courtesy of Dr. Sturgis. =EXTRA-LIMITAL= 18. DIDYMIUM INTERMEDIUM _Schroeter._ 1896. _Didymium intermedium_ Schroet., _Hedwigia_, Vol. XXXV., p. 209. 1902. _Didymium excelsum_ Jahn, _Ber. Deut. Bot. Ges._, XX., p. 275. Sporangia clustered or gregarious, discoidal and umbilicate below, or lobed or convolute, greyish white, stipitate; stipe pale yellow, tapering upwards, stuffed with lime crystals, expanding into the yellowish, discoidal, recurving columella; capillitium colorless, more or less branching; spores dark purple-brown, irregularly reticulate, 9-12 mu. Differs from _D. squamulosum_ in the reticulate epispore. Brazil.