NEW LABOULBENIALES. 707 



cell. Many of the species are furnished with 'trigger-organs,' which 

 arise as appendages from the apex of the perithecium, and evidently 

 function, like those of Ccrafomyces and other genera, as a means of 

 effecting a sudden and copious discharge of spores when they come in 

 contact with another host. 



Ilytheomyces elegans nov. sp. 



Basal cell of the receptacle minute, almost wholly hyaline, and 

 distinct fi'om the foot, bulging outward below the insertion of the 

 appendage: subbasal cell partly hyaline more or less deeply tinged 

 with blackish brown on the side next the host, this suffusion asso- 

 ciated with a more or less definite blackened protrusion or buffer; 

 about twice as large as the basal cell, its lower half lying beside the 

 latter, its upper half in contact, on its inner side, with the base of the 

 appendage. Basal and subbasal cells of the somewhat divergent 

 appendage opaque and indistinguishable, the androphorous cell small, 

 flattened, hyaline, so obliquely separated from the subbasal cell as to 

 occupy almost its whole inner margin; producing a large sessile 

 antheridium on the right side, wholly dark brown, except the apex of 

 the slightly outcurved neck, and on the left side a similar antheridium 

 which may or may not be associated with, or replaced by, an erect 

 variably developed sterile branch: the remaining cells of the nearly 

 straight, or Init slightly curved, axis usually five or six in number, 

 seldom more: each giving rise externally to a peculiar branchlet, its 

 base black, opaque, tooth-like, curved outward and bearing distally 

 from the upper convex surface a perfectly hyaline vesicular, variably 

 developed terminal portion; and also producing on the inner (upper) 

 side single branches, more or less appressed against the axis, and 

 branching; the lower branches more highly developed, the lowest 

 sometimes repeating on a smaller scale the branching of the axis as 

 a whole; the branches brown, the branchlets distally or wholly hya- 

 line. Stalk-cell of the perithecium black-brown, becoming opaque, 

 narrower below: hardly longer than broad, usually slightly pointed 

 distally ; the cells above hyaline, the region usually distinctly broader 

 than the base of the venter, and lying wholly above the primary 

 stalk-cell; the inner basal cell long and larger than the outer which 

 protrudes more or less distinctly above the smaller secondary stalk- 

 cell. Perithecium rather long and slender, slightly inflated near the 

 middle, or tapering slightly almost from its base; distally somewhat 



