THE GAMETOPHYTE 27 



shape, elongating and also becoming more or less flattened. One end becomes 

 narrower and sharply pointed, the other remaining thicker and rounded. The 

 reticulum at this time stains with great intensity and shows a tendency to coalesce, 

 which in the final stage results in an almost homogeneous, deeply-staining mass, 

 composed apparently of the completely fused chromosomes. In successful prepara- 

 tions the nucleus at this stage stains a clear carmine red, in strong contrast to the 

 bright violet of the blepharoplast. With the complete coalescence of the chromo- 

 somes the volume of the nucleus is noticeably decreased (plate i, fig. 19). The 

 blepharoplast forms a spirally coiled narrow band, from which the cilia can be seen 

 to grow, following its curve, but the blepharoplast is not in close contact with the 

 nucleus. 



The spermatocytes and the nuclei are rather smaller in Ophioglossum moluc- 

 canum than in 0. pendulum. In the older stages of the spermatozoid, the nucleus 

 in the former species is decidedly more elongated and more sharply pointed at both 

 ends (plate i, fig. 18). In this respect it more nearly resembles the spermatozoids 

 oi Botrychium and those of the true ferns; while in the larger, comparatively short 

 nucleus, as well as in some other respects, the spermatozoid of 0. pendulum is strik- 

 ingly like that of Equisetum. The number of cilia is large, but the exact number 

 could not be determined. 



Surrounding the spermatozoid and included in its coils is a considerable amount 

 of cytoplasm. I was not successful in obtaining any living spermatozoids, although 

 many attempts were made to do this, but in a number of sections of the opened 

 antheridium some were found in which the spermatozoids had been retained. While 

 these were usually more or less distorted, some were very well fixed and gave a good 

 idea of the structure of the free spermatozoid (plate 2, fig. 28). The cilia were 

 very much distorted in some cases, but in some they were clearly seen. There is 

 one thick posterior coil mainly composed of the nucleus, which is very much larger 

 than that of the sperm cell before it is discharged from the antheridium. The 

 nucleus has the form of a slightly coiled thick band, tapering somewhat at both ends, 

 but more markedly so in front. Beyond this extends a second coil, composed, 

 apparently, mainly of cytoplasm. This second coil extends into a third much smaller 

 one, which seems to be a flattened band along whose upper edge the blepharoplast is 

 closely applied (plate 2, fig. 28). The resemblance of the spermatozoid to that of 

 Equisetum. is very strong, but the nucleus is even more shortened than in the latter. 



The spermatozoid oi Ophioglossum pendulum is larger than that of any Pterido- 

 phyte that has yet been described. The cytoplasmic envelope and vesicle are not 

 very clearly separated and probably are similar to those of the free spermatozoids 

 of O. vulgatum or of Equisetum. Sometimes this protoplasmic envelope completely 

 surrounds the lower part of the spermatozoid and reminds one somewhat of the 

 peculiar spermatozoids of the Cycads. Owing to their large size, the spermatozoids 

 were often sectioned, and in some of the sections the blepharoplast was free from 

 the body of the spermatozoid and the attachment of the cilia was very easily seen 

 (plate 2, fig. 29, a). 



Mettenius figures the free spermatozoids of O. pedunculosum, but his figures 

 are certainly not accurate. Bruchmann, who has figured those of 0. vulgatum 

 (fig. 5, D), shows that they closely resemble the spermatozoids of the true ferns, but 

 are more massive, and the vesicle which envelops the posterior coils adheres more 

 closely to the spermatozoid than is usual in the ferns. In these respects it resembles 

 the spermatozoid of 0. pendulum. 



Jeffrey examined the development of the spermatozoids in Botrychium vir- 

 ginianum, which closely resemble those of Ophioglossum. Owing to the method of 



