VIII 



MARATTIALES 



279 



for some time shows the characteristic nuclear structure. The 

 origin of the ciha was not clearly made out, but there is little 

 question that they arise from a blepharoplast as in (jther cases 

 that have been more recently investigated. The free sperma- 

 tozoid (Fig. 152, I), is a flattened band, somewhat blunt behind 

 and tapering to a fine point in front; attached to a point just 

 back of the apex are several fine cilia. The body shows only 

 about two complete coils. 



Fig. 152. — Marattia DouglasU. Development of the antheridium. A-D, Longitudinal 

 section, X515; E-G, surface views, X257; H, ripe sperm cells; I, free spermato- 

 zoids, X1030; 0, operculum. 



The youngest archegonia are met w^ith some distance back 

 of the growing point, and apparently any superficial cell is 

 potentially an archegonium mother cell. The latter divides 

 usually into three superimposed cells (Fig. 153, A), of which 

 the lowest (b) forms the base of the archegonium. The basal 

 cell, however, may be absent in Marattia Douglasii, as is also 

 the case in Angiopteris and Dancea. From the middle cell by a 

 transverse division are formed the primary neck canal cell and 



