MONOGRAPH OF THE LAHOULBENIACE^E. 



267 



Dimorpiiomyces muticus Thaxtcr. Plate V, figs. 1-10. 



Proc. Am. Acad. Arts and Sci. Vol. XXIX, p. 104. 



Male individual, as in D. denticulatus, slightly larger, the basal and sub-basal cells often 

 more or less suffused posteriorly with blackish brown. 



Female individual, as in D. denticulatus, more rigid and flattened in habit, the perithecia and 

 appendages not bent away from one another. The perithecium larger, longer, proportionately 

 more slender, its apex truncate or but slightly oblique, the sub-terminal wall-cells producing no 

 tooth-like outgrowth. Spores 23-26 x 3/4. Perithecia 75-90 x 15/i. Total length to tip of 

 perithecium, 90-130/x. 



On Falagria dissecta Er., Waverly, Mass., and Kittery Point, Maine. 



This species occurs sometimes in company with the last on the same host. It is at once 

 distinguished by its larger unarmed perithecia, which never show any indication of the promi- 

 nence so characteristic of D. denticulatus. Its general habit, though it develops under identical 

 conditions, is also quite different from that of the preceding species, and no tendency to an an- 

 tero-posterior divergence is observable between the perithecia and appendages. The conforma- 

 tion of the tips of the perithecia in either case, as shown in figs. 7 and 13, is also xery 

 different. Four or even more perithecia are not rarely developed in this species, and in fig. 1 

 an instance is shown of an unusually highly developed individual in which the single primary 

 perithecium that remains is bent to the left, its fellow having been broken off or destroyed, while 

 five new secondary perithecia are developing on either side ; the youngest, at the extreme right, 

 consisting of a mere prominence not yet separated from the proliferating marginal cell described 

 in the preceding account of the genus. The same figure shows the remarkable phenomenon of 

 an almost complete development of two male spores within the old primary perithecium. The 

 species is more abundant than the preceding and more readily seen, from the greater size of its 

 projecting perithecia. 



DIMEROMYCES nov. gen. Plate IV, figs. 12-17. 



Dioecious. Male individual consisting of a series of superposed cells from which are pro- 

 duced, laterally, sterile appendages and antheridia in a single series. The antheridium com- 

 pound, consisting of a stalk-cell followed by four basal cells, above which are six antheridia! cells 

 arranged symmetrically in the same plane, and discharging the antherozoids into a common cavity, 

 whence they make their escape through a terminal orifice, at the tip of a long, slender, tubular, 

 terminal prolongation. 



Female individual like the male, the antheridia being replaced by perithecia. The latter 

 stalked, the cavity of the stalk-cell, basal cells and perithecium proper, eventually continuous, 

 through the absorption of all the septa. 



This is in some respects among the most interesting of all the genera of Laboulbeniacea?, 

 since it combines with a dioecious habit a more complicated development of the male individual 

 than is found in any other instance. In Dimorphomyces, to which it is more closely allied than 

 to any other genus, the antheridrum is nearly, if not quite, as highly developed; but it is always 



