OF ARTS AND SCIENCES. 183 



rounded prominence on one side ; the third cell of the series is sym- 

 metrically expanded upwards, large and broad, more or less tinged 

 with brown and surmounted by the circle of appendage bearing cells 

 (about fifteen in number), which are more or less irregular in size and 

 subtriangular in outUue. The appendages consist commonly of a 

 single large long slender flattened cell, its external surface bearing very 

 numerous branches succeeding one another in a single vertical row, 

 the lowest ones simple, beak-like, curved outwards ; others higher up 

 bearing beak-like brauchlets, while certain of the upper branches may 

 resemble the main cell from which they arise, and like them bear one 

 or more terminal branchlets which may in turn be more or less copi- 

 ously branched, the whole forming a dense tuft about the stalk of the 

 perithecium of very complicated structure. Perithecia, one or two 

 in number, arising from cells indistinguishable within the circle of 

 appendages, straight, basally slightly inflated, distally subcylindrical 

 and tapering abrujrtly to a symmetrical truncate apex ; borne on a 

 very elongate stalk which raises them far above the appendages and 

 consists of a cylindrical very long basal cell terminated by three cells, 

 one as long as and opposite the other two. Spores 40 X 4 /x. Peri- 

 thecia 120-140 X 22-26 fi. Stalk (longest) 480 fi. Appendages 

 (longest) 185 /m. The main basal cell (longest) 130 fx. Receptacle 

 110-130 jjL long ; width at base 7.5 fx, at apex about 45 /x. 



On abdomen of Acylophorus pronus Er., Massachusetts ; A. Jiavi- 

 collis Sachs, Pennsylvania. 



DICHOMYCES, nov. gen. 



Receptacle flattened, bilaterally symmetrical, multicellular above a 

 narrow stalk cell, terminated by two clearly defined transverse rows of 

 cells: the sub-terminal cells of the lower row modified to form, anteri- 

 orly, single projecting tooth-like antheridia : the upper series bearing 

 a pair of perithecia and several sterile apjDcndages all symmetrically 

 arranged. Appendages as in Peyritschiella, simple, cylindrical. Peri- 

 thecia symmetrical. 



This genus is closely allied to Peyritschiella from which it is dis- 

 tinguished by its bilateral symmetry and the constant presence of a 

 pair of perithecia reaching maturity simultaneously. In the above 

 description the term anterior is applied to the slightly convex side 

 from which are produced the two short and sharp projections which 

 are analogous to the single similar projection found in Peyritschiella, 

 and represent highly developed single antheridia. 



