268 



MONOCxRAPH OF TIIE LABOULBENTACEiE. 



solitary, and the receptacle is very greatly reduced, being quite different from that of the female ; 

 while in the present genus it differs only in its slightly smaller size. The antheridium is almost 

 identical in structure with that of Dimorphomyces, from which it differs only in its more slender 

 and elongate form, and in its free stalk-cell. The perithecium also, when mature, shows the same 

 remarkable absorption of its basal septa which one finds in the last-mentioned genus, its whole 

 cavity, from the apex to the insertion of the stalk-cell, becoming continuous about the time that 

 the spores begin to mature. The trichogyne, as far as can be determined from a somewhat im- 

 perfect specimen (fig. 17), is small and irregularly inflated. 



The receptacle is quite unique in structure, and apparently in development. The material 

 available does not, unfortunately, illustrate the complete development, there being no very 

 young stages ; but it is evident that the young plant ends with a single primary appendage, 

 which is the upper one of the series in the mature individual. Then, by successive divisions 

 of the basal cell of the receptacle, new cells appear to be cut off from its distal end ; each of 

 which, in its turn, cuts off a small cell, always on the same side, from which the secondary 

 appendages, the perithecia, and the antheridia are directly developed. A somewhat similar 

 arrangement of organs is found in the female individual of Dimorphomyces ; but in this case the 

 series are twofold and the proliferations terminal from wing-like lateral outgrowths. 



Dimeromyces africanus nov. sp. Plate IV, figs. 12-18. 



Male individual brownish. Receptacle consisting of usually seven very obliquely superposed 

 cells, from all of which, except the basal, may be developed on the side which is uppermost, a 

 sterile appendage or an antheridium in no regular order except that the terminal cell always 

 bears an appendage. Antheridia rarely more than three, usually two, somewhat flattened, borne 

 on a short free stalk-cell, the basal cells small, the six antheridial cells in two transverse rows 

 of three each, the neck long and slender, slightly curved, its base distinctly inflated. The 

 appendages simple, rigid, septate, tapering, becoming blackish brown ; the sub-basal cell somewhat 

 constricted and deeply suffused with blackish brown. Antherozoids about 2.5 x .75/u, rod-like. 

 Antheridia, including stalk-cell, 60 x 1G>, the neck, including its inflated base, about 38/x. 

 Receptacle, 125-150 x 35^. 



Female individual like the male, but larger; the receptacle usually consisting of eleven cells, 

 the antheridia replaced by banana-shaped perithecia, one to four in number, short-stalked, 

 brownish ; the distal end more deeply suffused, and tapering somewhat abruptly to the broadly 

 truncate apex. Spores once septate 75 x 5.5/x. Perithecia, 140-175 x 26-35/i, including stalk- 

 cell. Appendages (longer), 175-260/a. Receptacle, 120-150 x 35-50/x. 



On Pachyteles luteus Hope, Mt. Coffee, Liberia (O. F. Cooke). 



The types of this interesting form were found on two specimens of the host which were 

 among the insects kindly loaned me for examination by Professor Cooke, and occurred on the 

 inferior surface of the abdomen near the base of the two posterior pairs of legs. I was not able 

 to determine from the material whether the sexes always grow in pairs, since from their position 

 of growth it was not possible to remove a portion of the chitin bearing them without injuring the 

 insect. It is altogether probable, however, that the development of the spore pairs corresponds 

 to that of the other dioecious forms (Amorphomyccs and Dimorphomyces). 



