96 



THE AMERICAN MONTHLY 



[May, 



The part they play in the life-history 

 of the plant, though transient (their 

 movements not lasting longer than 

 five mmutes m the antherozoids of 

 Isoetes, and but from one half to three 

 quarters of an hour in Selaginelld), is 

 of the greatest importance. After their 

 short but active life they disappear 

 by being absorbed into the female or 

 germ cell. Thus Pringsheim has 

 observed the entrance of the sperma- 

 tozoids into the protoplasm of the 

 oosphere in CEdogonium and Vaii- 

 cheria, as Strasburger has also in 

 regard to Ferns, while Hofmeister 

 observed that they entered the arche- 

 gonium of Muscineas. 



The spermatozoid or antherozoids 

 are usually many hundreds or even 

 thousands of times smaller than the 

 oospheres which they fertilize. At 

 times they become attached to the 

 oosphere in such numbers that their 

 combined movements are sufficiently 

 energetic to impart to the large 

 oosphere a rotatory motion, lasting 

 for half an hour or more (Fucacece). 



The great variety of the male cells 

 becomes especiilly conspicuous if we 

 compare the roundish swarmspore- 

 like spermatozoids of CEdogonium 

 and ColeochcEte with the bacillary 

 spermatozoids of Saprolegnia {Achxia 

 dioicd) and with the spiral filiform 

 antherozoids of the Characeae, Mus- 

 cinete and Vascular Cryptogams the 

 coils of which vary in number from 

 two to three {Nitella) to twelve or 

 thirteen {Marseliii). In every case is 

 the form adapted to produce the right 

 kind of motion, in order to convey the 

 fertilizing substance to the female 

 cell, in a manner harmonious with its 

 structure. With the performance of 

 its function as a fertilizing element, 

 the presence of cilia has only to do in 

 so far as it is the means of bringing 

 about the contact of the male with the 

 female cell; then it is that its chemico- 

 vital properties come into play, these 

 properties being of course character- 

 istic of the male element. 



Algae are distinguished from the 

 rest of Cryptogams by their sperma- 



tozoids never being in the form of 

 slender spiral filaments, but always 

 short and rounded, at least, at their 

 posterior ends. In most algas they 

 resemble swarm-spores, but are usu- 

 ally much smaller (one half as large 

 in Saprohgnid) and are provided with 

 a red corpuscle. The mode of for- 

 mation of antherozoids in the mother- 

 cell is somewhat as follows : The 

 contents of the cell appear to be per- 

 fectly homogenous, no nucleus is ap- 

 parent, and the antherozoid originates 

 from a shining granular mass of pro- 

 toplasm which encloses a vacuole. In 

 some cases (e. g. Isoetes) the cilia at 

 one end are formed first, and the 

 spirally formed body becomes differ- 

 entiated afterwards by a sort of split- 

 ting of the protoplasm from before 

 backwards. In Isoetes the antherozoid 

 is spirally coiled about the central 

 vacuole, which, being surrounded by a 

 fine membrane, not unfrequently re- 

 mains attached to its posterior ex- 

 tremity after it has escaped, and is 

 carried along with it. In other cases 

 (Filices, Rhizocarpere) it is only the 

 parietal portion of the contents of the 

 mother-cell which goes to form the 

 filament and cilia, while the central 

 part, as a vesicle filled with colorless 

 granules, or with starch grains and 

 sap, remains for sometime attached to 

 the posterior or thickened end of the 

 filament. This vesicle is not a part 

 of the antherozoid since it subse- 

 quently falls off, and remains at rest, 

 while the filament alone continues in 

 motion. 



The number of spermatozoids pro- 

 duced by one mother-cell varies from 

 one (Filices, Rhizocarpex, Lycopodia- 

 ceae) to one hundred, or one hundred 

 and fifty (Equisetace^e). From the 

 commencement of gennination up to 

 the complete maturity of the anthero- 

 zoids there is (in Isoetes, e. g.) an in- 

 terval of about three weeks. Like 

 zoospores, they sometimes begin to 

 rotate even while yet within the 

 mother-cell (Characece, e. g.). As a 

 rule, the filaments are perfectly clear; 

 at times, however, a few glistening 



