Bacteriologie. — Lichenes. — Palaeontologie. 125 



active agglutinating serum which has been heated to destroy the 

 Opsonins, are agglutinated and are then englobed by the leucocytes; 

 30. typhoid bacteria which have been grown in agglutinating serum, 

 heated or not heated, are also absorbed; 4^. while active aggluti- 

 nating serum prepares the microbes for inception by the phagocytes, 

 the so-called chemical agglutinating substances do not possess this 

 property; and 5". the röle of agglutinin is, therefore, to coat the 

 bacteria with a precipitate which is positively chemotactic towards 

 the leucoc5^tes; and thus, by facilitating the absorption of the microbes, 

 agglutination plays an active part in immunity. Autorreferat. 



Campbell, D. H., Germination of the Spores of Ophio- 

 glossum. (Annais of Botany. Vol. XX, 59, 1906. p. 321). 



The spores of O. Mohiccanum germinate freely. A small amount 

 of chlorophj'll occurs in the young prothalli, the largest obtained 

 consisted of four cells. O. peiiduluni and O. intennediuni germinate 

 much more slowly. Chlorophyll was not detected in either of these 

 cases but in the latter a mycorhiza was present in all plants that 

 had grown beyond the three-celled stage. 



M. Wilson (Glasgow). 



Arber, E. A. N., On the Past History of theFerns. (Annais 

 of Botany. Vol. XX. p. 215—232. with a diagram in the text, 1906). 



This paper embodies a reexamination of the evidence for the 

 existence of the three great groups of modern Ferns in Mesozoic 

 and Palaeozoic times. It is concluded that, as is already generally 

 agreed, the Leptosporangiatae were, in the Mesozoic period, in the 

 Position of a dominant group, and most of the families still exiSting 

 had then become differentiated. 



But in the Palaeozoic period it seems doubtful if we can distinguish 

 clearly between two groups, the Ensporangiate and the Leptosporan- 

 giate. It is more probable that the members of the Fern alliance, 

 which then existed, although not in the later Palaeozoic forming a 

 dominant group, were really an ancient stock, from which the 

 Mesozoic Leptosporangiatae were derived. For this ancient group, 

 the name Primofilices is suggested, and the Botryopterideae are 

 regarded as being the, at present, best-known familywithin that group. 



As the result of recent research on the nature of the male and 

 female organs of the Cycadofilices, which has tended to show that 

 many of the Fern-like fructifications occurringin the Palaeozoic rocks, 

 formerly regarded as belonging to Eusporangiate Ferns, are more 

 probably the male organs of Pteridosperms, it can no longer be held 

 that the Eiisporangiatae were a dominant group in Palaeozoic times. 

 Thus the Geological Record no longer Supports the conclusion 

 arrived at by some botanists from a study of the recent Ferns, that 

 the Eusporangiate is the more primitive type as compared with the 

 Leptosporangiate. 



The life-line of the Eusporangiatae can only be regarded at 

 present as obscure, so far as the Palaeozoic and Mesozoic rocks are 

 concerned. Even in the latter, little evidence of this race is to be 

 found. Certain fronds of Taeniopteris are perhaps the best examples 

 which have been put forward in this connexion, but even this genus 

 is not entireh^ above suspicion. As regards the Palaeozoic fructifi- 

 cations, formerly regarded as belonging to Eusporangiate Ferns, it 

 is impossible to say at present, which were really of this nature, 



