. The structure and development of mosses and ferns (Archegoniatae). rdlyso restricted as he figures. From the investigations of Shaw (2) and Belajeff (5, 6, 7),it is evident that the cilia arise from a blepharoplast. Belajeffconsiders the blepharoplast in the Pteridophytes, as well as inthe Bryophytes, to be a centrosome; but Shaw believes that theblepharoplast is an organ sui generis, and of quite differentnature from the centrosome. DC FILICINE2E LEPTOSPORANGIATyE 317 Mottier (3) has recently examined the structure of the sper-matozoid in Struthiopteris. He could detect no cytoplasmicenvelo
. The structure and development of mosses and ferns (Archegoniatae). rdlyso restricted as he figures. From the investigations of Shaw (2) and Belajeff (5, 6, 7),it is evident that the cilia arise from a blepharoplast. Belajeffconsiders the blepharoplast in the Pteridophytes, as well as inthe Bryophytes, to be a centrosome; but Shaw believes that theblepharoplast is an organ sui generis, and of quite differentnature from the centrosome. DC FILICINE2E LEPTOSPORANGIATyE 317 Mottier (3) has recently examined the structure of the sper-matozoid in Struthiopteris. He could detect no cytoplasmicenvelope investing the posterior coils, which seemed to be ofexclusively 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 timethe development of the spermatozoids commences. The muci-laginous walls stain now very strongly, and in a living stateappear thick and silvery-looking. The inner layer of thecell wall, however, remains intact, so that when the sperma-. FlG. 175.—Onoclea struthiopteris. A, Longitudinal section of the apex of a femaleprothallium, showing the apical cell {x) and a nearly ripe archegonium, X215;B-D, development of the archegonium; longitudinal sections, X430; h, neck canalcell. tozoids are ejected, they are still enclosed in a delicate cell mem-brane, which swells up as the water is absorbed and finallydissolves completely. The vesicle derived from the remainsof the cytoplasm is very conspicuous here, and the granularcontents usually, but not always, show the starch body of the free spermatozoid has the form of a flattenedband with thickened edges, which tapers to a fine point at theanterior end, but is broader and blunter behind. The peripheralcells of the antheridium become so much compressed by thecrowding of the sperm cells that they are scarcely perceptible. 3i8 MOSSES AND FERNS CHAP. but after the antheridium is burst open, the two
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