EXTERNAL MORPHOLOGY OF THE STEMS OF CALAMITES. "utat 
external features of a particular type the pith cast of which is known as 
Eucalamites cruciatus (Sternb). Grand’ Eury's term, however, is not only 
cumbersome, but it ean scarcely be retained now in view of the modern 
use of the word Culamodendron, as applied to one special anatomical type 
occurring among Calamites. The roots of the words Calamites and Calamo- 
dendron have an entirely distinct meaning, and thus Calamophloios appears 
to us to be preferable. 
The folowing table represents a preliminary attempt to correlate the 
specimens of British Calamites showing the external surfaces, so far as they 
are described in the present paper, with their corresponding pith casts. We 
prefer to keep the genus Calamites as a natural genus for the whole plant 
and not to confine it to fragments of pith casts as a form genus. The form 
genera which we apply to the external surfaces of stems are Calamophloios 
and Dictyocalamites, while for the jith casts we prefer Weiss's terms, 
Eucalamites, Stylocalamites, and Calamitina, as representing three as natural 
types as can be expected to be distinguished among such fossils. 
For further information on the correlation of other British and of foreign 
specimens the reader is referred to Kidston and Jongmans’ Monograph *. 
Correlation of the External Surfaces and Pith Casts of Calamites. 
TYPES OF EXTERNAL SURFACE. CORRESPONDING TYPES OF 
Piru Casts. 
Calamophloios britannicus (Kidston). (Unknown). 
Calamophloios congenius (Renault). Eucalamites cruciatus (Sternb.) pars. 
Eucalamites ramosus (Artis). 
Jucalamites paleaceus (tur). 
fi 
? Calamitina approximata (Brongn.). 
? Calamitina varians (Sternb.) pars. 
Calamophloios rugosus (Arber). 
Calamophloios Goepperti (Ett.). 
Calamophloios majus (Feistin.). ? Calamitina varans (Sternb.) pars. 
Calamophloios discifer (W eiss). (Unknown). 
Calamophloios Sachsei (Stur). Calamitina Sachsei (Stur). 
Calamophloios undulatus (Sternb.). Calamitina undulata (Sternb.). 
Calamophloios verticillatus (L. & H.). ? Calamitina varians (Sternb.) pars. 
Calamophloios Suckowi (Brongn.). Stylocalamites Suckowi (Brongn.). 
(Unknown)? cf. P1. 24. fig. 19. Stylocalamites Cisti (Brongn.). 
Dietyocalamites Burri (Arber). (Unknown). 
* Kidston & Jongmans (1915). 
