218 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the appendage, while the other forms the base of the outer series of 

 wall-cells of the perithecium. The appendage consisting of a series 

 of superposed cells bearing scattered branchlets. Perithecium many- 

 celled, indeterminate, without distinction of venter and neck, ap- 

 pendiculate on the inner side below the tip. 



This genus, of wliich two other species are known on Ilydrocharis, 

 one from North America, and another from Africa, appears to be 

 intermediate between Ceratomyces, which it resembles most nearly 

 in the characters of its perithecium, and Rhyncophoromyces, which" 

 possesses a similar indeterminate receptacle. Although in the present 

 species, which is taken as the type, several appendages develop in a 

 compact group below the apex of the perithecium, in the African form 

 there is only one which is very similar to that seen in species of Cera- 

 tomyces. The North American form, of which I have only one un- 

 developed individual, shows that the sperm-cells -are developed 

 exogenously exactly as in Rhyncophoromyces. 



Synaptomyces Argentinus nov. sp. 



Receptacle consisting of a series of about twenty superposed, much 

 flattened, cells; surmounted by two somewhat unequal cells separated 

 from one another by an oblique septum; a transversely elongated 

 rounded cell lying obliquely between the anterior of the two and the 

 basal cell of the appendage, which is more or less conspicuously 

 indented externally. The appendage somewhat broken in the types, 

 its basal or subbasal cell giving rise to a simple branch, the main axis 

 of undivided superposed cells proliferating to form several slender 

 branches, which arise from its tip. Perithecium relatively large and 

 stout, hardly inflated above the base, slightly narrower distally, the 

 papillate tip abruptly distinguished; the apex broad and asymmetri- 

 cally rounded, the perithecial appendages arising in a group just below 

 the tip on the anterior side, usually three being superposed; their 

 extremities free, their bases laterally coherent, some of them proli- 

 ferating to form slender terminal hyaline branchlets. Perithecium 

 335X80-390-105 /u; its appendage without terminal branchlets 110- 

 120 /i. Receptacle 250-275X70-80 (x distally. Appendage (broken) 

 160X 15-18 IX. Total length to tip of perithecium 700-750 ix. 



On the left inferior margin of the thorax of Hydrocharis sp.. No. 943, 

 Palermo, near Belgrano. 



