DC 



FILICINE2E LEPTOSPORANGIATyE 



317 



Mottier (3) has recently examined the structure of the sper- 

 matozoid in Struthiopteris. He could detect no cytoplasmic 

 envelope investing the posterior coils, which seemed to be of 

 exclusively nuclear nature. The vesicle showed a fine cyto- 

 plasmic reticulum in which the larger granules were imbedded. 



The separation of the sperm cells begins at about the time 

 the development of the spermatozoids commences. The muci- 

 laginous walls stain now very strongly, and in a living state 

 appear thick and silvery-looking. The inner layer of the 

 cell wall, however, remains intact, so that when the sperma- 



FlG. 175. — Onoclea struthiopteris. A, Longitudinal section of the apex of a female 

 prothallium, showing the apical cell {x) and a nearly ripe archegonium, X215; 

 B-D, development of the archegonium; longitudinal sections, X430; h, neck canal 

 cell. 



tozoids are ejected, they are still enclosed in a delicate cell mem- 

 brane, which swells up as the water is absorbed and finally 

 dissolves completely. The vesicle derived from the remains 

 of the cytoplasm is very conspicuous here, and the granular 

 contents usually, but not always, show the starch reaction. 

 The body of the free spermatozoid has the form of a flattened 

 band with thickened edges, which tapers to a fine point at the 

 anterior end, but is broader and blunter behind. The peripheral 

 cells of the antheridium become so much compressed by the 

 crowding of the sperm cells that they are scarcely perceptible. 



