MONOGRAPH OF THE LABOULBENIACEiE. 



375 



superposed cells. The posterior row terminates opposite the base of this appendage in a bilobed 

 prominence beyond which tbe short more or less pointed apex is often strongly bent to or towards 

 the base of the peritliecial appendage. Antheridial appendage short and stout, usually less than 

 one third as long as the perithecium, sub-conical, with numerous branches produced from its 

 inner side, slender, rather rigid, with more or less divergent branch! ets. Receptacle consisting 

 of three superposed cells, followed by two cells ; the posterior larger and followed by the basal 

 cells of the appendage ; the anterior much smaller, followed by a second cell about equalling it 

 in size, beyond which follows the base of the perithecium : the basal cell wholly or partly hya- 

 line or translucent above the large jet black foot ; the remaining cells deeply blackened except 

 along their anterior edges, the blackening involving the base of the antheridial appendage. 

 Spores, 110-120 x 4 ^. Perithecia, 280-300 x 65-70 fi, longest, 330 fi, its appendage, 180-200 fi. 

 Total length to tip of perithecium, 400-525 /a. Antheridial appendage (exclusive of its 

 branches) about one third as long as the perithecium. 



On Tropisternus glaber Hb. and T. nimbatus Say, Milford, Connecticut ; Arlington, Mass.; 

 Kittery Point, Maine. 



This species, though perhaps the commonest member of the genus, seems never very abun- 

 dant. It is subject to a good deal of variation in size, but is otherwise very constant in its 

 characters and easily distinguished from the rarer C. confusus. It is found on the lower surface 

 of the abdomen and thorax of its host, especially along the margin of the former on the left side, 

 and is conspicuous from its large size. 



It may be mentioned that this species, and probably the succeeding, is subject to the external 

 parisitism of a Chytridiaceous parasite of singular structure resembling the Obelidium of Nowa- 

 kowski in some respects, but apparently belonging to an undescribed genus. The development 

 of this plant has not, however, been as yet fully made out. 



Ceratomyces confusus Thaxter. Plate XXIV, figs. 11, 12. 



Proc. Am. Acad. Arts and Sci. Vol. XXX, p. 480. 



General habit and color as in C. mirabilis. Perithecium hardly inflated, its inner margin 

 curving evenly to the prominent blunt apex which stands out free from the base of the perithecial 

 appendage. The perithecial appendage shorter and usually stouter than in C. mirabilis, without 

 the bulbous inflation at its base. Axis of antheridial appendage long and slender, distally 

 attenuated, with comparatively few short branches. Receptacle as in C. mirabilis. Spores, 

 75-90 x 3.7 fi. Perithecia, 235-335 x 65 Axis of antheridial appendage 235 \x (longest). 

 Receptacle, 165 x 75 \i. 



On Tropisternus glaber Hb. and T. nimbatus Say, Milford, Connecticut, and Kittery Point, 

 Maine. 



This species is much rarer than C. mirabilis, and is at once distinguished by the absence of 

 any posterior prominences below the apex of the perithecium, as well as by the differences 

 presented by its perithecial and antheridial appendages. Its spores also seem constantly smaller, 

 and although the two species are so strikingly similar, it is unlikely that they are mere varieties 

 of a single form. It occurs, like the preceding species, along the inferior margin of its host's 

 body, but almost always on the opposite (right) side. 



