MONOGRAPH OF THE LABOULBENIACE^. 



279 



cept that there appear to be not more than four antheridial cells (Plate II, fig. 12), which dis- 

 charge into a common cavity above. The latter forms the slightly inflated base of the terminal 

 conical portion of the organ, the anthcrozoids, which are comparatively minute, making their 

 way through a pore at its apex. 



The pcrithecia, except in P. geminata, are usually solitary, and arise normally from the dis- 

 tal cell-series ; but in abnormal cases they may be produced externally from the sub-distal or 

 even the lower series (P. geminata). In structure, the pcrithecia present no great peculiarities ; 

 the cell-rows containing each four cells, the lip-cells being usually characteristically papillate, 

 and symmetrical or nearly so. The ascogenic cell is commonly solitary (Plate I, figs. 27-31); 

 but in some instances there appear to be two. The trichogyne, in the few cases in which it has 

 been observed, is very rudimentary, consisting of a vesicular prominence, sometimes showing a 

 tendency to produce slight protuberances, as in the case of Camptomyces. 



The four known species all occur on terrestrial beetles belonging to the Carabidae and 

 Staphylinidce, and on account of their small size and appressed habit are usually detected with 

 difficulty. 



In the following descriptions the side which bears the antheridia is spoken of as the anterior, 

 the opposite as the posterior face of the individual. The antheridium may thus be described as 

 occurring on the left side. 



Peyritschiella curvata Thaxter. Plate II, fig. 12 ; Plate IV, figs. 11-18. 



Proc. Am. Acad. Arts and Sci. Vol. XXIV, p. 8. 



Pcrithecia hyaline, nearly straight, tapering to the symmetrically four-lobed apex, bent at an 

 angle to the axis of the receptacle, the curvature of which it continues. Receptacle consisting 

 of two superposed cells, followed by two transverse series of cells of variable numbers (four to 

 seven) ; the terminal bearing one, rarely two, perithecia, with a group of sterile appendages on 

 either side, the sub-terminal producing on one side, the sharply pointed antheridium with or 

 without one or more adjacent sterile appendages ; on the other side a group of from one to 

 three similar appendages. Appendages simple, cylindrical, continuous, or pseudoseptate, hya- 

 line, sometimes becoming tinged with brownish. Spores, 26 x 3.5-4 p. Perithecia, 90-100 x 

 22-29 (jl. Appendages (longer), 60 /x. Total length to tip of perithecium, 280-300 fi. 



On Platyrms cincticollis Say. Vicinity of New Haven, Conn., of Cambridge, Mass., and of 

 Kittery Point, Maine. 



The more common species of the genus occurring on the right shoulder of its host, and 

 sometimes on the adjacent edge of the elytra. It is distinguished from the three remaining 

 species by the absence of the lower transverse series of cells, the sub-basal cell of its receptacle 

 remaining undivided at maturity. In very rare instances, two perithecia may be borne on a 

 single individual; but I have seen but two cases of this kind among some dozens of specimens. 

 The curved habit of the species is doubtless due to its position of growth upon the host, and is 

 a character of little importance. The beetle on which it is found is common in the localities 

 mentioned, along small brooks, where it may be found, concealed beneath stones, sticks, and rub- 

 bish generally, in shady places. 



