X] CALAMITINA. 



373 



rather deep nodal constrictions ; the branch-whorls being repre- 

 sented by a series of pits on the nodal constrictions recurring 

 at corresponding intervals to the whorls of branch-scars on the 

 surface of the stem. Leaves narrow and linear in form, like 

 those on Asterophyllitean branches, are occasionally associated 

 with this type of stem. 



Fig. 101, Catamites (Calamitina) sp. From a specimen in the British Museum. 



(After Carruthers.) Slightly reduced. 



The fragment of a Calamitina stem shown in tig. 101 is the 

 counterpart of a specimen originally figured by Steinhauer^ in 

 1818 as a species of Phytolithus. This may be specifically 

 identical with C. Gopperti ; but it is better to speak of so small 

 a specimen as merely one of the Calamitina stems, to be com- 

 pared with Catamites (Calamitina) Gopperti. The specimen 

 measures 14*5 cm. in length and 7 cm. in breadth. 



The form of pith-cast represented in fig. 100 is no doubt that 

 of one of the Calamitina species, but as it is seldom possible to 

 determine the connection between such casts and the particular 



' Steinhauer (18), PI. vi. fig. 1. 



