280 



MONOGRAPH OF THE LABOULBENIACE2E. 



Peyritschiella geminata Thaxter. Plate IV, figs. 7-8 and 24. 



Proc. Am. Acad. Arts and Sci. Vol. XXIX, p. 101. 



Hyaline. Receptacle asymmetrical, consisting of a single basal cell followed by three succes- 

 sive, more or less definite, transverse rows of cells. The lowest of these rows is the most variable 

 and irregular, consisting of from two to four cells, one of which, larger than the rest, is an axile 

 cell continuing the basal cell directly, while the remaining one to three cells are cut off from 

 it on one side, each successive cell smaller and placed higher in the series, the outermost and 

 uppermost bearing one of the sterile appendages characteristic of the genus. The second row 

 also consists of a larger median cell, which is free for a short distance on one side, and on both 

 sides of which are cut off, as in tbe first row, from two to four cells, the smaller uppermost ones 

 on both sides giving rise to from one to three appendages, according to the number of the cells. 

 The upper row is either symmetrical or asymmetrical, according as it gives rise to two or to only 

 one perithecium. In the first instance it consists of a median cell, above which are produced 

 two sterile appendages, and a variable number of cells cut off laterally as in the lower rows, but 

 nearly symmetrical in size and shape, the outermost bearing sterile appendages. If one perithe- 

 cium only is produced, the row is asymmetrical, and a greater number of appendages appear 

 on one side of the perithecium than on the other. Peritbecia very slightly inflated near the base, 

 tapering abruptly but slightly to the spreading apex, which is four-lobed, the lobes rounded, 

 large and prominent. Spores about 37 x 3.7 fi. Peritbecia, 75-80 x 18-22 /x. Total length to 

 tip of peritbecia, 220-260 /jl (150 in specimens from tbe smaller host). 



On Pterostichus luctuosus Dej., P. erythropus Dej., and P. patruelis Dej., Kittery Point, 

 Maine ; Arlington, Mass. 



Unlike the other species, this form not infrequently produces two peritbecia, the arrangement 

 of its distal cells in such cases closely resembling that of Dichomyces. The main body of the 

 receptacle is, however, asymmetrical, and the antberidium occurs only on one side. 



It is distinguished from the preceding species by its more slender form, smaller and shorter 

 appendages and perithecia, and especially by the division of the sub-basal cell of its receptacle 

 to form an incomplete transverse series, or rather half-series, of cells. Its antberidium is small 

 and inconspicuous, occurring on one side as in the other species. It may be found growing on 

 the inferior surface of the prothorax near its anterior margin, and on the adjacent posterior 

 margin of the prothorax, as well as on the anterior legs. In the last position the individuals be- 

 come very considerably distorted in form, and in such specimens several instances have been 

 observed in which perithecia were developed from the lower and middle transverse series of cells 

 on the right side (opposite the antberidium). 



The species is a rare one, though the hosts which it infests are not uncommon under stones 

 or in rubbish near the margins of ponds or streams. 



Peyritschiella minima Thaxter. Plate VI, figs. 19-21. 



Proc. Am. Acad. Arts and Sci. Vol. XXIV, p. 266. 



Hyaline or slightly yellowish. Perithecia somewhat asymmetrical, large, stout, tapering 

 rather abruptly to the blunt apex, which terminates in four not very prominent, nearly symmetri- 



