28 



in common with our specimen, — namely — the 

 Lepidodendron Steinheckicmum of Goppert, * and the 

 Lepidodendron undulaitim , or Aspidaria undidata, of 

 Sternberg 2 . It resembles the former only in contour, 

 and differs from it — firstly — in the absence of a central, 

 curvilinear ridge , extending from the superior to the 

 inferior edge of the areola; and — secondly — in respect to 

 the size of the areolae, which is about four or five times 

 larger than that of Goppert's species. 



The two figures of Sternberg, it must be confessed, 

 are exceedingly dissimilar , notwithstanding the well 

 supported supposition of the specific identity of their 

 prototypes. Our specimen coincides with both only in 

 respect to the form and situation of the central scar, 

 while the points of difference are important and numer- 

 ous. A rhomboidal form of the areolae, and a margin- 

 al developement between them characterize the so-called 

 Aspidaria undidata in distinction from our species, while 

 the Lepidodendron undidaium differs from the same in 

 the convexity of its areolae, and in the presence of a 

 central ridge. 



Taking advantage of his privilege, the author has 

 named this species after his distinguished teacher and 

 friend, Professor Beyrich of Berlin. 



Locality, in coal formation, — Pennsylvania. 



J Gopp. Syst. fil. foss. p. 466, pi. 41 , figs. 4,5 ; Unger, Gen, 

 et Spec. p. 258. 



2 Sternb. Vers. 1, ps. 11, 21, pi. 10, fig. 2; II, p. 182, pi. 68, 

 fig. 13 ; Unger, Gen. et Spec. p. 259; Brong. Prodr. p. 86. 



