214 



MONOGRAPH OF THE LABOULBENTACEiE. 



pens, the production of antheridia is greatly increased (Plate II, fig. 8). Further ref- 

 erence to this circumstance will be made in connection -with the " abnormal forms " 

 described below. 



Turning to the compound type of antheridium we find much less uniformity than in 

 the simple type just described, although the antheridial cells which make up the essen- 

 tial portion of this organ are practically identical with the simple antheridium. 

 As has been already mentioned, these cells seem to be intercalary in origin as far as 

 can be determined in the absence of a knowledge of their early development, 

 and instead of being wholly or partly free, both the necks and venters are closely 

 united below, beside or around a common cavity into which they discharge. Of the 

 twenty-seven genera thus far described, about one-third are characterized by possessing 

 this compound type of antheridium, and since that occurring in Dimeromyces is one 

 of the largest and most easily studied, it may be taken as an illustration. In this 

 genus the species are dioecious, and the male individual reaches a maximum differen- 

 tiation, being as well developed as the female, and bearing more than one anthe- 

 ridium (Plate IV", fig. 16), which possesses a stalk-cell and four basal cells lying below 

 the antheridial cells. The antheridial cells in this case are six in number, symmetri- 

 cally arranged in two rows, their venters large and emptying through long narrow 

 canals into the somewhat inflated base of the long and slender " secondary " neck 

 which serves as a common medium for the final discharge of the products of all the 

 antheridial cells. The latter here correspond closely to those previously described in 

 connection with the simple antheridia, and the formation from them of antherozoids is 

 also similar in all respects. The canal, however, does not enlarge, as in the simple 

 form, immediately after leaving the venter; but continues about the same diameter 

 till it has nearly reached the general cavity at the base of the secondary neck, when 

 it expands slightly. As a result, the antherozoids remain in connection with the proto- 

 plasm of the venter till they project some Tittle distance into the cavity of the sec- 

 ondary neck, eventually separating from it and falling free into this general 

 receptacle, whence, as represented in the figure, they may be seen at various points 

 making their way out. The antheridium of Dimorphomyces is essentially identical 

 with that just described, the male individual in this genus, however, producing but a 

 single antheridium (Plate V, figs. 8-9 and 14-15). In Peyritschiella (Plate II, fig. 

 12), Dichomyces and Enarthromyces (Plate III, fig. 19), although the antheridium is 

 somewhat different in form, the secondary neck being less prominent and less 

 abruptly distinguished, its general structure is also essentially the same ; the four to 

 six antheridial cells in the last mentioned genus lying somewhat obliquely side by 



