124 THE SAPEOLEGNIACE^ OF THE UNITED STATES, 



of development within the limits of a single variety. The name stelligeea has 

 been chosen of the two used by Cornu, to avoid confusion with A. spinosa DeBary, 

 which is a very distinct species, in spite of the fact that it is quoted in Saccardo's 

 Sylloge ('88) as a synonym of A. racemosa var. spinosa Cornu. 



Besides the spiny oogonia and the fewer oospores, one observes that in this variety 

 the antheridial branches are, on the whole, even shorter than in the type-form, and 

 more frequently arise from the wall of the oogonium itself than in the latter. 



In February, 1891, I received, through Dr. J. B. Paige, of the Massachusetts 

 Agricultural College, some trout eggs from the Northampton fish hatchery, which were 

 evidently attacked by a fungus of this family, and were dead. The hyphse failed to 

 develop sexual organs, but fresh cultures, obtained by throwing flies into the vessel 

 containing them, produced a new crop, bearing the sexual organs of this form. I was 

 unable to visit the hatchery, but am informed that it proves necessary to remove dead 

 eggs very frequently, since the infection spreads rapidly, and all the eggs in the 

 hatching trays are killed unless this is done. After the eggs are hatched, the young 

 fry appear not to be injured by the fungus. If this be true, the present species would 

 seem to possess less parasitic capacity than the fungus of the salmon disease. It is 

 probable that, in case of the eggs, the fungus can attack only the non-living egg- 

 membranes, and that the death of the living cells of the egg is an indirect and not a 

 direct result of its attack. 



This variety may represent a transitional form between some smooth and spiny 

 species of Achlya, not only as regards their oogonial structure, but also in the reduc- 

 tion of the antheridial branches, which is carried even to their entire disappearance in 

 some spiny species. 



Achlya oUgacantha DeBary ('88). 



111. : DeBary. '88, PI. X, Fig. 1. 



The present species has delicate hyphsB which bear globular oogonia with rather 

 few spines, and commonly four to eight oospores each. Antheridia are developed on 

 all the oogonia from rather elongate, simple branches of androgynous or diclinous 

 origin. It has been observed by DeBary in a single culture from Baden, but not yet 

 elsewhere. It may be regarded as representing a spiny form of the polyandra type, 

 and in this respect differs from the spiny species to be described, which do not 

 resemble closely any of the smooth-walled species, but constitute a distinct group of 

 forms. 



