MR. А. В. HORWOOD ON CALAMITES SCHÜTZEI, ETC. 281 
Node A (the short internode) appears to serve the purpose of imparting 
additional strength to the stem owing to the weight of branches above. The 
same feature will be noticed in recent Zquiseta. The specimen, as is usual in 
this species, is covered with carbonaceous matter. 
The specimen from Brighouse, Yorkshire, provisionally referred to this species 
is a stem 2 ft. 9 ins. long, somewhat arched, being possibly an upper portion 
of a subterranean stem, having grown out at an angle. There are 18 inter- 
riodes devoid of a carbon-crust, with only here and there traces of branch-scars. 
Tt exhibits the same features as the Stanton-under-Bardon specimen, there 
being a uniform increase in length and a regular succession of short internodes. 
The tables of measurements of the two taken together afford an interesting 
means of comparison with those of recent Æquiseta. 
Brief reference may be made to previously published measurements of 
other specimens of Calamites. 
In the * Fossil. Flora, Lindley and Hutton * figure a specimen referred to 
Calamites approximatus, Sternberg (= C. Schützei, Stur), with 12-13 short 
internodes, followed by six increasing regularly in length. The former are 
abnormal, and due possibly to remarkable strain and need of extra strength. 
Otherwise it is intermediate between Calamitina and Eucalamites. 
In his memoir on the South Wales Coalfield Dr. Kidston figures f an 
interesting specimen of Calamites (Calamitina) varians, Sternb., var. insignis, 
Weiss. In length it is 32150 mm., and contains two complete and three 
incomplete periods, with forty internodes, and a short internode precedes each 
branch-bearing node. 
In his memoir on the Somerset Coalfield also Dr. Kidston figures ў a 
specimen of Calamites' (Eucalamites) senarius, Weiss. It is 36*7 ст. long with 
18 internodes, and 6 branch-scars are seen. It exhibits the same uniformity 
in length of internodes with gradual inerease in each period noticed in the 
specimens here under notice. 
Professor Seward gives measurements $ of internodes of specimens of 
Calamites (Calamitina) undulata, Sternb. 
In his memoir on Calamites || Prof. Williamson mentions the occurrence 
of this short internode, but finds no reason for its constant recurrence or 
significance. Referring to a specimen of Mr. Wilde’s (pl. 27. fig. 29), he 
says :—“ The drawing is of natural size. In the two lowermost internodes 
(k, k') and to a large extent in the uppermost one (4^, the longitudinal grooves 
are regularly parallel with each other and, like the internodes themselves, 
uniform in size; but in the shorter internode (£^) this is not the case. 
* Vol. i. pl. 77, 
T Trans. Roy. Soc. Edinb. vol. xxxv. pt. ii. no. 10 (1889), pl. 1. fig. 1. 
I Ibid. vol. xxxiii, pt. ii. (1887) рр. 340-1. 
$ Geol. Mag. 1888, p. 2. 
| Phil. Trans. Roy. Soc. 1871, pp. 495-6. 
