4 o6 SCIENCE PROGRESS. 



which ultimately breaks up into four branches to supply the 

 sporangia. A fact of special interest in connection with the 

 spores, is the frequent occurrence of feebly developed sister- 

 cells. Speaking of this, Williamson and Scott suggest that 

 in these small spores we have "the beginning of spore- 

 abortion, involving improved nutrition of the surviving- 

 spores". In another form of Calamostackys, C Casheana 

 Will., " the same process, carried further in certain 

 sporangia, has led to the formation of specially favoured 

 macrospores " ; these facts point to Calamostackys as "a 

 genus in which the first rise of the phenomenon of hetero- 

 spory can be traced ". 1 



In 1 8 8 7 2 Williamson described a strobilus with a typical 

 calamitean axis as "the true fructification of Catamites"? 

 This has since been named Catamites pedunculatus Will, 

 and Scott. In assigning a specific name to this cone it 

 would, perhaps, have been better to draw up a concise 

 specific diagnosis ; as it is, one is left to formulate a 

 definition from the published figures and descriptions. 

 In this strobilus the sporangiophores are borne at the base 

 of the coherent bracts or disks, conforming in this respect 

 to Weiss' type Palceostackya ; each sporangiophore bore 

 four sporangia, but no peltate expansion has been seen in 

 the specimens hitherto examined. 4 



Having attempted this very brief and imperfect summary 

 of Catamites, we may endeavour in the shortest possible 

 manner to answer the question : " How far does Catamites 

 agree with Equisetum in essential morphological characters?" 

 Putting aside the absence of true secondary thickening in 

 the recent equisetaceous species, the " primary structure, on 

 which mCalamites the secondary zone is superposed, is almost 



1 Williamson and Scott, p. 911. 



2 This form of cone was first described by Williamson in 1869, but the 

 specimens were much less complete than those figured in the later paper 

 (1887). 



3 Williamson (5). 



4 Another form of Calamostachys has recently been described by 

 Hick and Lomax, and named by them C. oldhamia {Manchester Lit. and 

 Phil. Mem. and Proc, p. 1, 1894). 



