SEXUAL REPRODUCTION. 



277 



the form of the sperm is usually that of the cell in which it 

 is produced. If it is set free, it may become globular, and 

 have slow amoeboid movements, or it may be entirely im- 

 motile. In the latter case it must depend upon the move- 

 ments of the water into which it escapes for transference to 

 the vicinity of the egg. The sperm may be ovoid and fur- 

 nished at the end with one or more cilia; or elongated and 

 bent or coiled one or more times. The elongated forms 

 have almost invariably two to many cilia (fig. 306). 



381. The spermary.- -The organ in which the sperms are 

 produced is the spermary or antheridium. It is either simple 

 or compound. A simple spermary consists of a single cell 

 whose contents is transformed into one or more sperms. 

 Simple spermaries occur only in algre and fungi, and by 

 reduction among seed-plants. (See ^[ 

 385.) If more than one sperm is to be 

 formed, the nucleus, originally single, 

 becomes divided into as many parts as 

 there are to be sperms (sometimes into 

 more than become mature). The total 

 number of sperms produced by a plant is 

 related somewhat to the number of eggs, 

 but particularly to the chances of the 

 sperms reaching the egg. 



. . FIG. 307. -The sex organs 



If there is but a single sperm formed of i\-ronosf>ora. k, 



hypha which has devel- 



by each spermary, either the number 01 oped at the end the 



ovary, c, containing a 



spermaries is great or some adaptation single egg (the central 



dark sphere). //', hypha 



exists for the certain transfer of the sperm which has developed the 



. spermary, //, whose pro- 



to the egg. In Cystopus and its allies, toplasm, constituting a 



single sperm, is passing 



for instance, a branch of the spermary through the fertilizing 



tube (a branch of the 

 grOWS into the OVarV, through which the spermary) into the egg. 



Magnified 350 diam. 

 Sperm passes to the egg (fig. 307). After DeBary. 



A simple spermary arises either by the differentiation of 

 one of the ordinary cells, or of a special lateral branch, as in 



h 1 



