208 



Bernard Smith — A Lepidodendroid Stem. 



Supra-occipital entering largely into the foramen magnum. Pro- 

 cessus parotici not raised. Large fossa bypoparotica present. 

 Dermal armour present and well developed. Ossified dorsocaudal 

 tendons run along neurapophysis and chevron bones, and augmenting 

 in number towards the end of the tail. 



EXPLANATION OF PAGE-ILLUSTEATION (p. 207). 



It will be noticed 



from one another, 



This is an unusual 



III. — On a Lepidodendroid Stem from the Coal-measures. 



By Bernard Smith, B.A., Sidney Sussex College, Cambridge. 



AMONG the numerous Lepidodendroid remains in the Geological 

 Department of the British Museum (Nat. Hist), there is one 

 which presents several characters of unusual interest. It is a cast, 

 obtained from the Middle Coal-measures of South Staffordshire, near 

 Dudley, and belongs to the Johnson Collection.' 

 A portion of the specimen is figured on p. 209. 

 that the mammillated leaf-cushions are distant 

 and are separated by broad bands of striated bark, 

 feature in the case of British Lepidodendra. The preservation is 

 fairly good, except in the details of the leaf-scar. In the specimen 

 thirteen leaf-cushions are represented, forming portions of five spiral 

 series. The cushions are rhomboidal in outline, and at first sight 

 do not appear to be very sharply marked ofi" from the bark. On 

 closer inspection, however, they are seen to be moderately well 

 defined, although the lateral angles are flattened and obscured by 

 the encroachment of the bark. They measure from 1'8 to 2 cm. in 

 length, and from 'G to -7 cm. at their greatest width. The upper 

 and lower extremities lie in one plane, which is the median plane 

 of the cushion, and are inclined neither to the right nor to the left 

 (cf. Lepidodendron serpentigerum) . The cushions stand out in high 

 relief, and depart somewhat from the form of a low truncated pyramid 

 so commonly seen amongst Lepidodendra. However, this is in no 

 wise remarkable, for examples of Lepidodendra having raised cushions 



Register ed number V. 1233. 



