378 



MONOGRAPH OF THE LABOULBENIACEiE. 



Ceratomyces rostratus Thaxter. Plate XXIV, figs. 18-27. 



Proc. Am. Acad. Arts and Sci. Vol. XXVIII, p. 188. 



Reddish or amber-brown. Receptacle long, slender, expanding slightly upward, consisting 

 of about twelve superposed cells. Perithecium consisting of a clearly distinguished neck and an 

 inflated oval basal portion, completely filled with spores and asci, which pushes the appendage to 

 one side and continues directly the axis of the receptacle; the neck very elongate, irregularly 

 cylindrical, straight or its terminal portion at maturity (in perfectly developed specimens) 

 abruptly bent upon itself, the recurved portion tapering slightly to the hunched asymmetrical 

 apex ; the cell-rows made up of seventy cells, more or less. Appendage arising from a broad 

 base flattened at maturity by pressure from the base of the perithecium, consisting of about six 

 superposed cells bearing numerous branches, which may in turn be several times branched. 

 Spores about 75 x 3.5 Perithecia, basal portion, 110-150 x 65-90 n ; neck, including recurved 

 portion, longest, 1.17 mm. Appendage about 90-100 fx long, its longest branches about 200 /i. 

 Receptacle, large, about 260 fi long by 55 /jl at the distal end. 



On Hydrocombus jimbriatus Melsh., Massachusetts, Texas ; Philhydrus cinctus Say, Maine. 

 A variety on P. nebulosus Say, Maine. 



The most remarkable species of the genus, the enormously elongated neck of the perithecium 

 becoming hooked only in fully mature specimens, and serving an evident purpose in the spoive 

 dissemination during coitus. 



In perhaps a majority of specimens the neck is shorter and straight, and there are 

 very considerable variations in size and form. The appendage is often very broad at its 

 base, and projects outward, often at a considerable angle ; while its basal cells may be 

 irregularly divided and produce branches which, in some cases, even seem to arise from the 

 lower perithecial wall-cells, forming a rather dense tuft, while in other cases they are more 

 sparingly developed. The number of cells composing the receptacle is subject to considerable 

 variation ; and the cell-rows of the perithecium present very great differences in the number of 

 their component cells. Unlike any other species, there is a distinct differentiation between the 

 terminal conductive portion of the perithecium and its inflated ascigerous base, which is, appar- 

 ently through pressure of its contents, hardly distinguished in many cases from the base of the 

 appendage. The antheridial branches and the antherozoids of this species, which are peculiar 

 in many respects, have been already alluded to (p. 210). The typical form is probably widely 

 distributed, and is not uncommon in the brook below the cascade at Waverly and in some other 

 localities about Boston. A few specimens were also obtained from a Texan specimen of Hydro- 

 combus in the Museum collection, and it occurs rarely on Philhydrus cinctus at Kittery Point, 

 Maine. A small variety which should not, I think, be separated specifically from the present 

 form, occurs on the lower surface of the elytra of P. nebulosus Say, near the tip or the outer mar- 

 gin, and is represented in figs. 26, 27. Although so very much smaller, and apparently always 

 confined to the situation mentioned, it possesses no essential differences by which it can be dis- 

 tinguished from many forms of the present species, which is found on the inferior surface of the 

 abdomen and thorax of its host and not unfrequently on the legs. It is subject to the attack of 

 a chytridiaceous parasite similar to that which occurs on C. mirabilis, but specifically distinct. 



