488 W. C. Stiirgis — Type-Si^ecimens of Myxomycetes. 



which are almost as much reduced in length as those characteristic 

 of 0. brevlfila. The genus Trichia also, presents the same varying 

 feature, it being not uncommon to find specimens of T. affinis, DBy,, 

 in which all of the elaters are thus reduced. Taking these facts 

 into consideration, it seems quite impossible to regard Oliyonema 

 brevijila, Pk, other than as a variety of 0. flavidum, Pk. 



It may not be out of place here to record the fact that typical spe- 

 cimens of neither Oligonema nitens nor 0. flavidum and its varieties, 

 commented upon above, show characters which serve to unite them 

 with the very beautiful form described by Mr. Morgan as Calonema 

 aureum. The latter, it is true, bears a very close external resem- 

 blance to Oligonema nitens, nor can we overlook the fact, regarding 

 the highly developed capillitium, that in the genus Trichia analo- 

 gous forms occur in which the normally free elaters are combined to 

 form a network; nevertheless the peculiar character of the sporan- 

 gium-wall in Calonema aureum., marked with scattered, raised 

 papillfe from which radiate countless fine veinlets, and the abund- 

 ant, strongly developed capillitium marked with reticulate ridges, 

 faint spirals and prominent rings and spines, are combined features 

 practically wanting in the genus Oligonema, and serve to distinguish 

 that species from any other at present known to us. (PI. LXI, figs, 

 28 & 29.) 



Arcyria macrospora, Pk., Rep. XXXIV, p. 43, 1881, Both Lis- 

 ter and Macbride agree in referring this species to A ferrugineay 

 Saut., and examination of the type confirms their statements. The 

 dark, reddish-brown, ovoid sporangia, the coarse capillitium-threads 

 somewhat triangular in section and marked with anastomosing or 

 transverse bands and spinous processes, the large, pale-reddish, 

 minutely spinulose spores, and the beautifully reticulated cu^d, are 

 characters applicable to no other species. 



A somewhat peculiar effect is produced in this species upon treat- 

 ment with dilute potassium hydrate. In reddish-brown specimens 

 this color is rapidly dissolved out from the sporangium, capillitium, 

 and spores, leaving them of a uniform pale j-^ellow color ; in speci- 

 mens originally yellow or ochraceous in color, this is at first changed 

 by the alkali to a reddish-brown and then dissolved out. This lack 

 of stability in the coloring matter of this and some other species is 

 also seen in the rapidity with which it fades when exposed to direct 

 sunlight. 



We are now in a position to sum up the results of the foregoing 

 observations upon the species originally described by Professor Peck. 



