198 THE NORTH AMERICAN SLIME-MOULDS 



more narrow, 2-|- /i, warted, marked with blunt spinules, which 

 not infrequently pass into distinct transverse, narrow plates or 

 half-rings, free ends clavate and numerous ; spore-mass yellow, 

 spores by transmitted light smooth, granular, globose, 7-9 /u. 



This species as represented by the material before us seems 

 constant in size, color, and microscopic characters, in all which 

 it differs from all species here listed. It resembles somewhat 

 Laclmobolus globosus Schw., but differs in habit, habitat, color, 

 the capillitium, its attachment, and in the mode of dehiscence. 

 In the present species the wall is evanescent almost in toto ; in 

 L. globosiis it is remarkably persistent, and the capillitium is 

 adherent. Mr. Lister has seen fit to combine the last three 

 species of this list with L. globosus under one name, A. albida. 

 Inasmuch as the introduction of three varieties is apparently 

 necessary to carry out the scheme, its advantage to the student 

 is not conspicuous. 



Probably rare. Its smallness removes it from sight of all 

 but the most exact collectors. Maine, New York, South Caro- 

 lina, Alabama, Missouri, Iowa ; Black Hills, South Dakota. 



3. Heterotrichia Mass. 



1892. Heterotrichia Massee, Man. Myxogastres, p. 139. 



Sporangia distinct, stipitate ; the peridium simple evanescent 

 above as in Arcyria ; capillitium centrally attached, freely 

 branched, the threads within very slender, without broad, anas- 

 tomosing to form a dense peripheral network, and every- 

 where extended to form short, free, often hamate tips. A 

 single species, 







i. HETEROTRICHIA GABRIELL^E (Rav.) Mass. 



PLATE XIII., Fig. i, i a. 



1850. Arcyria gabriellce Rav. in litt. ad Cooke. 

 1892. Heterotrichia gabrielltz Mass., Mon., p. 140. 



Sporangia crowded or gregarious, oblong cylindric or ovoid, 

 at first red, becoming yellowish brown, stipitate ; the peridium 



