MONOGRAPH OF THE LABOULBENIACE/E. 



217 



the opening in the diaphragm into the cavity of the neck, and this protruded portion, 

 having reached a definite size, becomes separated as a free mass of protoplasm, which, 

 having been, as a rule, moulded to a cylindrical form in the cavity of the neck, makes its 

 exit through the terminal pore. When lice, the endogenous antherozoids exactly re- 

 semble baeilli or cocci in appearance, becoming rounded at the ends so that the short 

 tonus are almost spherical (Plate I. fig. 20 ; Plate VI, fig. 5 ; Plate II, fig. 2 ; Plate III, 

 fig. 19). Their substance is refractive and homogeneous, and I have been unable, by 

 staining, to differentiate a definite nucleus. Although, when first separated from the 

 contents of the venter, they are undoubtedly naked protoplasmic masses, in some 

 cases at least a thin wall seems to be secreted around them after their exit from the 

 antheridial cell. In Hnarthromyces, for example, which possesses antherozoids larger 

 than those of any other known form, such a wall appears to be present, and the same 

 may very probably bo the case in other forms in which the antherozoids are so minute 

 that exact observations in this respect are made with difficulty, even after they have 

 become attached to the trichogyne. When freshly discharged they are usually suffi- 

 ciently characteristic in appearance to be readily distinguished from the bacteria and 

 yeasts which are often so numerous on certain individuals as to completely corticate 

 the appendages. 



The discharge of the antherozoids from the antheridial cell is a slow process, and 

 probably does not occur more frequently than once every two or three hours ; at 

 least this is about the rate observed in individuals which have been separated from 

 the host and placed in water. It may be, however, that the rate is more rapid under 

 natural conditions ; since the parasite does not survive very long after separation from 

 the host, which doubtless disturbs not only its nutrition, but also its general tumes- 

 cence. From the secondary neck of compound antheridia the discharge is, of course, 

 often much more rapid at times, and a dozen or more antherozoids may be seen to 

 make their exit within a few minutes after an individual of Camptomyces, for ex- 

 ample, has been mounted in water. Cultures of the antherozoids in water, continued 

 for many days, have never shown any indication of an attempt at development. 

 Reference has already been made to the duration of the active period of the anthe- 

 ridia, and it remains to note the fact that the numbers of antherozoids formed during 

 this period from a single antheridium must be counted by hundreds, or even thou- 

 sands, in the case of the more highly-developed compound forms. 



Female Sexual Organs. — It has been previously mentioned that in a majority of 

 forms the antheridial appendage is developed from the terminal cell of the germina- 

 ting spore. The female organs, however, are always formed from the products of 



