308 CALAMARIEAE. 



the casts of Equisetitae, and illustrated also by a figure in the text of one of 

 Dawson's publications 1 . The roots which spring from the nodes spread 

 at right angles into the adjoining rock. A similar but vertical narrowing 

 is said to occur also in the much rarer branch-bearing upper extremities, 

 as for example in Calamites Cistii 2 . From his observations Grand' Eury 

 classes the following from among the better-known species with his genus 

 Calamites : ' Calamites Suckowii, Brongn., C. Cistii, Brongn., C. ramosus, 

 Artis, and C. cannaeformis, Schloth.' On the other hand he claims 

 Calamites cruciatus, Stbg as a cast of Calamodendron, to which according to 

 Weiss' 3 determination certain forms with a very thin rind of coal (Calamites 

 multiramis 4 ) also belong. I regret that I have never as yet had an op- 

 portunity of making myself acquainted with these differences on the spot, 

 which, as may be imagined, cannot be demonstrated at all or only very 

 imperfectly in a Museum. I once indeed saw in the Museum in Paris a 

 large basal portion of Calamodendron, which was intended to be a standard 

 specimen, but it gave me no clear picture. On a second visit I sought 

 for it in vain in its former position. 



The casts of Calamitae, in the widest acceptation of the term, have 

 been very recently made the objects of searching investigation by Stur 5 and 

 Weiss 6 . Some details of their external sculpture, which were not noticed 

 in our previous summary account of them, must now be taken into con- 

 sideration in connection with the exhaustive treatment which they have 

 received at the hands of these authors. 



By far the larger number of the specimens in the collections are 

 cylindrical pieces of casts or moulds broken off at both ends. This condition 

 causes a difficulty in determining the upper and lower extremities. The 

 pieces with short internodes and narrowed into a conical form at one end, 

 which are also far from rare, are generally believed to answer to the bases 

 of erect shoots ; the grounds for this belief are the facts observed in Equise- 

 tites, and the circumstance already mentioned that they are sometimes found 

 in actual connection with the stem, which bears them 7 . If, indeed, upper 

 extremities of a similar kind were to occ\ir, as Grand' Eury affirms that they 

 do, some caution would be necessary in this respect. Such an extremity 

 might be present for example in the lateral branch of Calamites ramifer 

 figured in Stur 8 . Longer portions of the branch-system with the parts in 

 attachment are much less common ; Weiss has figured a certain number of 

 them ; in these specimens the upper and lower ends can generally be deter- 

 mined from the direction of the lateral branches. But these branches are of 

 two kinds. The one kind has been already described ; the others on the 

 contrary are cylindrical and do not narrow at the base, but are attached by 



1 Dawson (13), p. 195. s Grand' Enry (1), t. 2, f. i. 8 Weiss (5). 4 Grand' 



Eury (1), t. 10, f. 2 and t. 12. * Stur (5). Weiss (5). 7 Weiss (5), t. 2 ; t. 3, 



f. 2 ; t. 4, f. I, and Williamson (1), IX, t. 21, f. 30. " Stur (5), p. 156, f. 17. 



