Devclo^mient of the Antheri'dimn in Ferns. 237 



The last explanation of the development of the fein-anthe- 

 ridinm Avhich Ilofmeister gives, in the English edition of his 

 * Vcrglcichende Untersuchungen'*, does not differ essentially 

 from his former one. He says, " The analogy to be derived 

 from the process of development of the antheridia of the Mus- 

 cinea3 renders it probable that the large central cell is formed 

 by the production of an excentrical, inclined, longitudinal 

 septum in the young antheridium, followed by the production 

 of another exccntrical septum cutting the latter at right angles, 

 and the subsecpient formation of a longitudinal septum cutting 

 both the above at an angle of 45°, such formation taking place 

 after the apical cell of the antheridium has been isolated by a 

 strongly inclined, almost horizontal septum cutting the primary 

 longitudinal septum. When the central cell is surrounded by 

 two zones of enveloping cells, it is manifest that the two zones 

 originate in the transverse division of the primary single zone." 



Lastly, Strassburgerf has occupied himself with the present 

 subject. In Pteris serndafa, according to him, the mother 

 cell of the antheridium is divided first of all by two oppositely 

 inclinexl septa, which are set obliquely upon the bottom of the 

 antheridium and cut its side Avails nearly at their summit. 

 ^' These first two septa are soon followed respectively by two 

 other opposite ones, cutting them at an angle of 45°. All 

 these four septa are strongly inclined together towards the 

 base of the antheridium, without, however, absolutely meeting 

 there ; and in this way a central quadrangular space is cut off, 

 which is widened above in a funnel-like form. The upper 

 part of the antheridium is still unicellular ; but a number of 

 divisions soon occur in it. First of all, four upper lateral cells 

 are produced in exactly the same way as the inferior ones ; 

 they arc set upon these inferior ones, and inclined together 

 towards the apex of the antheridium. Finally, between these 

 upper lateral cells an opercular cell, of the form of the seg- 

 ment of a sphere, is separated from the vertex of the antheri- 

 dium. In this way a cellular body is formed, consisting of a 

 central cell, eight lateral cells, and an opercular cell. The 

 central cell, seen from above, is quadrangular, bellied out in 

 the middle of its height, gradually diminished toAvards its ex- 

 tremities, especially the loAver one, and it becomes the primi- 

 tiA^e mother cell of the spermatozoids. It contains an abun- 

 dance of protoplasm and a distinct cell-nucleus, Avhilst the 

 lateral cells as yet contain only a fcAV chlorophyll-grains." 



* On the Genniiiation, Development, and Fructiiication of the higher 

 Cryptoganiia (London, 1862),' p. 180. 



t " Die Refruchtung bei den Farrnkrautcm," M6m, de I'Acad. de 

 St. P<$tersb. 18G8, p. 2. 



