364 SCIENCE PROGRESS. 



From what has now been said it will be seen that as 

 regards the sporophyte the Anthocerotese show an advance 

 on other Liverworts and approach the Pteridophyta : they 

 appear in fact the most probable link we possess between 

 Bryophytes and Pteridophytes ; though we recognise this, 

 the gulf between them is still a very wide and deep 

 one. 



The Mosses {Musci) have been by various writers held 

 to occupy an important position in the main line of descent 

 of the Archegoniatse, and it is only in comparatively recent 

 times, and as the result of late work, that the opinion has 

 gained ground that they are, as Campbell has expressed it, 

 "a very clearly defined class, and that their relationship 

 with other forms is at best a somewhat remote one" (/. c 

 p. 216). "The Mosses, like the foliose Liverworts, seem to 

 represent a modern, extremely specialised type, with no 

 direct connection with higher forms. Undoubtedly related 

 to the Anthocerotese through Sphagnum, their further de- 

 velopment has diverged farther and farther away from the 

 other Archegoniatae, until in the Bryinese both gameto- 

 phyte and sporophyte have little in common with them." 

 The grounds for this change of opinion must be carefully 

 considered. 



Since the time of Mettenius the very obvious com- 

 parison had been drawn between the protonema of Mosses 

 and the filamentous prothallus of the Hymenophyllacese : 

 the delicacy of texture of the leaves appeared to support 

 this comparison. It was extended, on an enlarged basis ot 

 facts, by Goebel [Ann. dujard. Bot. rfe Bidtenzorg, vii.) ; and 

 if, with him, we assume that the oldest archegoniate forms 

 were filamentous, with the sexual organs directly inserted 

 upon a branched cellular filament, it would appear that the 

 Filmy Ferns, and especially Tric/ioinanes, approach such a 

 primitive form : at the same time the affinity of these to 

 the Mosses would appear to be indicated, and in Bux- 

 baumia Goebel believes that he has found the most 

 primitive form of Moss. As long as we proceed mainly 

 upon the mere formal comparison of the gametophyte, and 

 relegate considerations of the structure of the sexual organs 



