MONOGRAPH OF THE LABOULBENIAOEyE. 



285 



than any of its allies. I have met with it on one occasion only, when several hosts were 

 collected from a heap of rubbish near cultivated land, on which the parasite occurred in great 

 numbers, thickly covering the lower surface of the abdomen and extending to the legs and 

 thorax. Unfortunately, all but one of these hosts made their escape in transit, but the single 

 one remaining has furnished abundant material of the mature form. Owing to its light color, 

 large size, and more than usually divergent, though not erect, habit of growth, it is not readily 

 overlooked on the black abdomen of its host. 



CHITONOMYCES Peyritsch, Plates VIII and XXVI. 



Sitz. d. k. Acad. d. Wiss. LXVIII, p. 250 (1873) ; Heimatomyces Peyritsch, 1. c. p. 2. r >l ; Heimatomyces emend., Thaxter. 



Proc. Am. Acad. Arts and Sci. Vol. XXVJI, p. 30. 



Receptacle consisting of a basal and a terminal portion ; the former consisting of two 

 superposed cells, and three or four upper smaller cells which form the base of the perithecium ; 

 the latter consisting of four cells lying beside the perithecium, the terminal cell always free, 

 originally more or less dome- or bell-shaped, bearing a single terminal appendage, and sometimes 

 becoming otherwise modified at maturity ; the sub-terminal cell connected on its inner side with, 

 or rarely free from, the two cells below it, from the upper of which is separated a small cell 

 that bears terminally, in the angle formed by the perithecium and the receptacle, one or two 

 appendages, beside which is situated the usually small antheridium (?). Appendages slender, 

 filamentous, simple, aseptate or spuriously septate, hyaline, evanescent, the base blackened and 

 slightly constricted. Perithecium more or less completely united to the distal portion of the 

 receptacle, each series of wall-cells containing not more than six cells, some of which may be 

 appendiculate ; the apex often variously modified. Spores fusiform, once septate. 



Since the description of numerous species under the name Heimatomyces, I have had an 

 opportunity of examining specimens of Chitonomyces melanurus Peyritsch, and, as I formerly 

 suggested, the two genera prove identical. I have therefore concluded to use the latter name to 

 distinguish the genus ; since, although I very much dislike to regard the rules of priority at the 

 expense of those of common sense, it seems desirable that the nomenclature adopted in the 

 present monograph should be, in so far as possible, a fixed one, and the name Chitonomyces 

 undoubtedly has precedence in the present instance to the extent of nearly half a page. 



The genus is one the position of which has been, until the present paper was in press, quite 

 uncertain ; the character of the sexual organs not having been ascertained with sufficient exact- 

 ness to warrant any definite statement concerning them. The very recent discovery, however, 

 of an undescribed and very closely allied aquatic genus, in which the antheridium is so placed 

 that it can be readily seen, renders its position no longer doubtful, and confirms my first impres- 

 sion, which was based on the general resemblance of its appendages and the structure of its 

 receptacle to those of Peyritschiella. The new genus, a description of which is necessarily 

 reserved for a succeeding supplement, is characterized by a general structure curiously inter- 

 mediate between that of Chitonomyces and the genus last mentioned, the small but very definite 

 compound antheridium occupying a position on the anterior margin of the plant just below the 

 base of the perithecium. 



