302 



CALAMARIEAK. 



example of Arthropitys bistriata from Chemnitz, in the museum of the 

 Provincial Geological Institution at Leipsic, in which the medullary tube is 

 not rilled up, but allows the inner boundary of the woody body to be seen 

 in all its details. Four nodes are visible as transverse projecting lines ; the 

 short internodes show regular longitudinal striation, in which the ridges 

 correspond to the bundles of the medullary sheath, and the furrows to the 

 primary rays. By means of squeezes with gutta-percha Stur has obtained 

 the picture of the cast of the specimen, which answers absolutely to an 



FIG. 40. Arthropitys from Chemnitz. Petrified woody body, showing where it borders on the pith the normal 

 striation and articulation of the casts of Calamitae. A view of the transverse section with the wedges of wood. 

 B longitudinal section. After Stur (s). 



ordinary cast of Calamitae, and shows the lines of the nodes as transverse 

 furrows. The bands of the medullary rays now appear of course as ribs, 

 the bundles of the medullary sheath as furrows on the surface. Almost as 

 beautiful is the specimen represented on another table 1 , an Arthropitys 

 from the Rothliegende of Neu-Paka in the Museum of the Imperial National 

 Institution. A portion of the quartz which filled the medullary tube came 

 away from the two halves, and the surface of the cast thus preserved pre- 

 sented the picture of one of the Calamitae with all the characteristic details 



1 Stnr (8), p. 453, f. 10. 



