NEW FEATURES IN CALAMITES AND EQUISETACEÆ 279 
Тв. Remarks on the fistular pith-cavit of Calamites. 
On their figure of a specimen referred to Calamites inequalis, Lindley and 
Hutton* remark that “ the specimens confirm the opinion that Calamites were 
hollow. The cylinder that once was of vegetable matter has altogether a 
different texture from the interior, which is a coarse grit that separates freely 
from the stem itself." The confirmation merely rests upon the presence of a 
carbon erust, whieh is usual where preservation has been in shales, not 
sandstones. 
Many previous observers had figured casts, e. g. Scheuchzer, Volkmann, 
J. Woodward, C. F. Schulze, Suckow. Schulze even compared the speci- 
mens with Equisetacez. Suckow, author of the genus (1784), regarded them 
as casts, and compares them with Æquisetum maximum. Steinhauer, in 1818, 
figures casts, and Artis, in 1825, represents others in his * Antediluvian 
Phytology.' Brongniart, in 1822, compares Calamites with Equisetum; and in 
his * Histoire des végétaux fossiles, 1828, figures and describes many of the 
species now recognized. Thus Suckow paved the way for a correct concep- 
tion of their nature, which was later extended and improved by Dawes f, and 
in more recent times by the masterly work of Williamson, Scott, and others. 
Па, Deseription of specimens of Calamites with recurring 
short internodes, etc. 
The following measurements (Table I.) of the specimen of Calamites Schiitzet 
from Stanton-under-Bardon give in tabular form an idea of the regularity of 
the increase of internodes in length and uniformity of the short internode. 
The total length is 3 feet, width where split and where unsplit 3 inches. 
In another specimen from Brighouse, near Halifax, Yorkshire (Plate 19), 
the length is 2 ft. 9 ins, and the average width 23 ins. Its measurements 
are given below (Table II.). 
In the former case there are 21 internodes, of which the first and last may not 
be complete. "They may be divided into 3 complete periods. There is a notice- 
able inerease, regular and gradual, in each period commencing at the smallest 
internode. At the end of each period branches were borne, indications of 
which may be seen in the specimen. 
Below each node infranodal canals may be seen. 
The most striking feature is the uniform length (1:6 to 1:9 cm.) and 
position of the short internode at the commencement of each period. Again, 
internode B ranges from 3°5 to 4 cm., C from 4'7 to 5'7 ст., D from 
92 to 82 cm., and E from 5'5 to 7:1 ет. Thus there is a general uniformity 
in length. 
* Fossil Flora, vol. iii. 1837, pl. 176. 
T Quart. Journ, Geol. Soc. 1849, pp, 30-31; ibid 1851, рр. 196-99. 
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