Nos. 451-452.] STUDIES ON THE PLANT CELL. 577 



pigment spot and chromatophore. Those of the bryophytes and 

 the Lycopodinese are biciliate while other pteridophytes have 

 multiceliate sperms the cilia being distributed on a band 

 (blepharoplast) which lies along one side of the spiral structure. 

 A large portion of the spiral in these sperms is composed of 

 nuclear substance and much of the remaining cytoplasm with 

 granules and vacuolar inclusions may frequently be found in a 

 vesicle attached to the larger end of the spiral. 



The only motile sperm among the Fungi is that of Mono- 

 blepharis. The male cells of other Fungi are non-motile 

 bodies (spermatia) generally formed from the ends of delicate 

 filaments which are found in special organs called spermagonia. 

 Spermagonia have been described in the Uredinales, the lichens 

 and in the Laboulbeniaceae but their function is only clearly 

 established for the last two groups. They are very highly 

 differentiated in the Laboulbeniaceae and comprise several types 

 of structure. Another type of male cell, found in certain 

 groups of the Phycomycetes and Ascomycetes, is the ccenogamete 

 (to be described presently) which is however not the homologue 

 of the sperm but of the mother-cell or antheridium that develops 

 such structures. Sperms of the red Algae (Rhodophyceae) are 

 likewise non-motile and they are invariably formed singly in 

 small cells at the ends of filaments. These non motile sperms 

 of Fungi and red Algae are exceedingly small uninucleate bodies 

 without further complexity of structure as far as is known. 



We shall not attempt to discuss the earlier literature that 

 treats of the structure and development of the plant sperm. In 

 1894 Belajeff published a German translation of a paper 

 written two years before in Russian which presents the views of 

 previous investigators and to this the reader is referred for such 

 historical references. At that time various opinions were held 

 respecting the organization of the sperm, some writers (Campbell, 

 Guignard and others) believing that it was chiefly or wholly 

 nuclear in origin, while another group (Zacharias, '87, Belajeff, 

 Strasburger, '92, etc.) thought that the cytoplasm shared very 

 largely in its structure. Belajeff ('94a) from studies among the 

 Characeae showed with especial clearness that the cytoplasm 

 was an important constituent of this sperm since the nuclear 



