102 PROCEEDINGS OF THE AMERICAN ACADEMY. 



number of the cells. The upper row is either symmetrical or asym- 

 metrical according as it gives rise to two or to only one perithecium. 

 In the first instance it consists of an axile cell, above which are pro- 

 duced 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 perithecium 

 only is produced the row is asymmetrical and a greater number of 

 appendages appear on one side of the perithecium than on the other. 

 Perithecia 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 /x. Perithecia 75-80 

 X 18-22 p. Total length to tip of perithecia 220-260 p (150 p in 

 specimens from the smaller host). 



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

 Maine. 



Unlike the other species, this form not infrequently produces two 

 perithecia, 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 minute antheridium as far as can be 

 ascertained from the material obtained occurs only on one side. It 

 forms nevertheless an additional point of connection between the two 

 genera, which may ultimately have to be united, despite the extreme 

 differences between the type species in either case. 



Dichomyces infectus, nov. sp. 



Receptacle consisting of a short basal cell succeeded by an axile cell 

 placed vertically, on either side of which a series of three obliquely 

 superposed cells forms a blackened border. The remainder of the 

 receptacle consisting of two successive transverse symmetrical rows of 

 cells, the lower row made up of three central and several smaller ex- 

 ternal cells terminating on either side in a short blunt projection 

 below the prominent antheridia, beside which arise single sterile ap- 

 pendages. The distal row is composed of seven cells, the external 

 cells on either side not extending beyond the bases of the perithecia 

 and destitute of appendages ; two appendages arise between the peri- 

 thecia, one on either side. Perithecia two, closely approximated, 

 arising from single broad flattened cells, short and stout, tapering 

 slightly towards the subtruncate apex, which is destitute of papilla? or 

 appendages. Perithecia 66 X 22 p. Receptacle 60 X 40 p. 



On Xantholinns obsidarius Melsh. Waverly, Massachusetts. 



Two specimens of this small form were fonnd at the tip of the 

 abdomen of its host. 



