112 ROYAL SOCIETY OF CANADA 



The position of the leaf scars, and their form, as well as the 

 alternation of the ribs in the mutation of C. Cistii from the Little Eiver 

 group agrees with these typical forms from the Coal Measures of the 

 Joggins, and the epidermis is similarly striate, although the proportion 

 in the length of the intemodes and the width of the stem are those of 

 C. SucJcovii. 



Though we should give in this way a wide range of variation to 

 the characters of C. Cistii there still remains in the Devonian mutation 

 a marked difference in the width of the ribs as will be seen by com- 

 paring the dimensions of the Coal Measure with the Devonian forms, 

 the ribs of the latter being narrower. 



ASTEEOCALAMTTES, Schimper. 



I use the above generic name for the plants of the Little Eiver 

 group which Sir William. Dawson has described under the name Cala- 

 mités transitionisj Goepp. 



Mr. Eobert Kidston has traced tlie synonymy of this type through 

 Archseocalamites, Stur, and Bornia, as used by Lesquereux. He has 

 adopted Asterocalamites given by Schimper in 1862. The specific 

 name of the European species was given by Schlotheim in 1822-23. 



AsTEROCALAMiTEs RCORBicuLoiDES, n. sp. Plate I, Fig. 1. 



The distinction between this species and ^4. scorhiculatus is chief!}' 

 in the leaves. Lesquereux's description of Bornia radiata (A. scorhi- 

 culoides?) is as follows: — 



Stem cylindrical, articulate and furroived as in Calamités; articu- 

 lations scarcely contracted; rihs cut square or obtuse at the articulations; 

 continuous, not alternating , thinly striate; cortical cylinder thicTc; leaves 

 verticillate, free, linear lanceolate. 



Lesquereux has numerous specimens from the sub-conglomerate of 

 Alabama (Carboniferous) five to eight centimeters in diameter; "the 

 ribs seem very variable in width — one to three millimetres." He says, 

 *"■' the articulations are generally very narrow, cutting across the ribs, 

 which are thus continuous, parallel and without deviation. In some 

 rare cases the articulations are slightly contracted."' 



Schimper's description of the Europea,n species Archœo calamités 

 radiatus, Brgt.^ is as follows: — Stem erect arising from an arched base, 

 rooting, having a width of 2 to 10 cm., more or less elongated in the 

 joints, having the grooves continuous across the articulations, mould 



^ Zittel's Palseontology vol. Ill (Plants) p. 171. 



