THE GAMETOPHYTE 31 



the cover cell agree very closely with those in Ophioglossum; hut the neck cells are 

 more numerous and at maturity the neck projects much more strongly than is the 

 case in Ophioglossum. There may be as many as seven or eight cells in each row 

 of the neck, which, except that it is quite straight, resembles that of the typical 

 ferns. It is especially like that of Osmunda, in which the neck is also straight. The 

 neck canal cell (fig. 17, D) becomes much elongated, and the nucleus divides, as in 

 Ophioglossum, but in most cases at least there is no division of the canal cell itself. 

 As in Ophioglossum, the ventral canal cell is very inconspicuous, and often 

 impossible to detect. Jeffrey (fig. 17, E) figures a very evident ventral canal cell, 

 but the nucleus is much smaller than that of the egg or neck canal cell. I have also 

 found what seemed to be a ventral canal cell in the archegonium shortly before it 

 opened, but, as in the case of Ophioglossum, this was not absolutely certain. As 

 in the corresponding stage in Ophioglossum, above the egg cell, with its large and 

 conspicuous nucleus, there is a clear space containing a small round body, which 

 showed no evident nucleolus, but otherwise stained very much like the nucleus of 

 the egg, and was probably the nucleus of the ventral canal cell (fig. ij,D,v.) 

 While no certain cases of mitosis of the egg nucleus for the cutting off of the ventral 

 canal cell were encountered, in one case the egg nucleus looked as if it were in the 

 early prophase of division. Bruchmann's figures of the archegonium of Botrychium 

 lunaria closely resemble that of B.virginianum, but he was unable to find a ventral 

 canal cell, nor did he apparently see the division of the nucleus of the neck canal cell. 

 The archegonium of Helminthostachys (fig. 1 1,/)) closely resembles that of Botrychium. 



FERTILIZATION. 



In only a few cases were spermatozoids seen within the neck and venter of the 

 open archegonium in Ophioglossum, but twice a spermatozoid was seen within the 

 nucleus of the egg; as there were no other stages obtained, however, the details of 

 nuclear fusion could not be followed (fig. 16, //). The spermatozoid penetrates 

 the nucleus of the egg, where for a time it can be seen distinctly. It is probable 

 that its fusion with the egg nucleus is much like that described by Shaw for Onoclea 

 (Shaw 1, 2). In the mature egg cell the nuclear reticulum is often decidedly con- 

 tracted, but whether this is normal or the result of reagents can not be said. 



FERTILIZATION IN BOTRYCHIUM VIRGINIANUM. 



Jeffrey observed a single spermatozoid within the venter of the archegonium 

 and noted that at the time of fertilization the egg developed what he called a 

 "receptive prominence." I have observed the same phenomenon in several cases 

 (plate 2, fig. 46), and in a good many instances have also found one or more sper- 

 matozoids within the venter. In one case, what looked very much like a sperma- 

 tozoid was seen within the egg nucleus itself, and the process of fusion is probably 

 very much the same as that so fully described by Shaw for Onoclea. In the specimen 

 shown in fig. 17, F, one of the spermatozoids looks as if it has partially penetrated 

 the egg, but it is impossible to be certain that it was not simply lying against it. In 

 this case, just above the nulceus of the egg there was a slight break in the granular 

 cytoplasm that looked as if it might be a receptive spot, but the spermatozoid was 

 not entering the egg at this point. 



In another instance a curious thing was noted, but whether it was normal 

 or not it is impossible to say (plate 2, fig. 46). A spermatozoid had just enn 1. .1 

 the neck of the open archegonium ami the egg had developed a very conspicuous 

 receptive prominence. The nuclear contents were verj strongly contracted and 

 deeply stained and a portion apparently projected beyond the nuclear membrane 



