THAXTER. — RICKIA AND TRENOMYCES. 367 



(2.5-3 )Li). Spores about 25 X 2.5 /x. Total length to tip of perithe- 

 ciuin 40-70 n, to tip of posterior branch 50-175 /z. 



On Euzercon s\i\). No. 2431, Trinidad; No.223(),Manaos, Amazon; 

 No. 2058, Grenada, W. I. 



This species, and to a more marked degree the following, depart 

 greatly from the normal type, and would be placed in a new genus 

 with little hesitation were it not for the structure which characterizes 

 various others of the many undescribed species known to me. It is 

 evident that the "posterior branch" is an indeterminate proliferation 

 beyond the primary appendage, which appears to involve both the 

 "median" and the "posterior" marginal series of the more normal 

 forms. The receptacle, especially when a primary perithecium fails 

 to develop, may become variously branched and more than one 

 secondary perithecium may be produced. Antheridia of a type 

 like that of Distichomi/ccs appear to be developed externally on the 

 posterior branch nearer the base. The specimens from Brazil and 

 Trinidad seem to be identical, although those from Grenada, though 

 otherwise similar, are constantly somewhat smaller. 



Rickia arachnoidea nov, sp. 



Basal cell rather short and stout, the receptacle above it dividing 

 into two usually furcate arachnoid branches; an anterior on which a 

 perithecium is produced, and a posterior. Anterior branch indetermi- 

 nate, consfsting of two parallel series of cells usually not opposite, 

 irregularly appendiculate, furcate at a variable distance from its 

 base; one of the branchlets sterile, often greatly elongated; the 

 other short but variable, bearing a perithecium which on one side 

 is usually united to the upper six cells, some of them appendiculate, 

 which continue one of the two series forming the perithecial branchlet 

 which thus extends to the apex of the perithecium, beside which it 

 terminates in a short brown appendage: the perithecium long, slightly 

 and nearly symmetrically inflated, the tip bent distally abruptly 

 sidewise; the other row of the perithecial branchlet ending horizon- 

 tally or obliquely below the base of the perithecium and consisting 

 of from three to eight cells, some of which are appendiculate. Pos- 

 terior branch indeterminate, furcate, usually, just above its first to 

 fifth pair of cells, the cells of the two indeterminate branchlets not 

 paired, irregularly appendiculate, indeterminate, usually greatly 

 elongated: the second cell of the main receptacle below its furcation 

 bearing the large long nearly cylindrical basal and subtending cell< 



