264 



STIGMARIA. 



from the beginning. Their surface is smooth or slightly uneven, and is fur- 

 nished with shallow pits containing the fracture-scars of the appendages ; 

 these are in loose order and show regular quincuncial arrangement. The 

 positional relations which are at the foundation of this arrangement have 

 not yet, as far as I know, been accurately determined. The outline of the 

 Stigmariae is circular, and the boundary-line of their circumference is sharply 

 defined ; in the centre is a second circle, the central point of which is a dot- 

 like protuberance. Good figures are supplied by Schimper 1 , Heer 2 , and 

 Goldenberg 3 . 



The appendages are found in unusual abundance in immediate con- 

 nection with the axes ; where these occur as impressions in coal, the 

 appendages are scarcely ever wanting, and they spread out on the two sides 

 forming a right-angle with the axis. And when the rock is examined in 



which the casts of the axes 

 lie, every surface of division 

 in it is seen to be traversed 

 by the appendages, which 

 spread like rays on all sides 

 from its transverse frac- 

 tures. Where they lie free 

 their whole length through, 

 they appear as cylindrical 

 or dactyl iform bodies flatly 

 rounded at the upper ex- 

 tremity and suddenly contracted at the base, and having a smooth surface. 

 If they are pressed flat, as is always the case in impressions, the original 

 cylindrical form can usually be concluded from the longitudinal folds. The 

 finest specimens are those which are obtained by skilful use of the hammer 

 from the English calcareous nodules. These facts have all been given by 

 Steinhauer 4 in his excellent account of Stigmaria. Really good figures 

 (Fig. 30) are only rarely to be met with in the literature. Lindley and 

 Hutton 5 , Corda 6 , Sternberg 7 , and Zeiller 8 may be consulted. The fossil 

 is in fact so common that most authors have not thought it necessary to 

 give an illustrative figure. Sometimes, but not very often, the appendages 

 are dichotomously divided, and in that case each branch has its extremity 

 flatly rounded off in the usual manner. Goldenberg 9 and Corda 10 have 

 given figures of such cases. Goldenberg found an ovoid body in the bifur- 

 cation ; a similar body marked with a longitudinal furrow is represented on 



FIG. 30. Stigmaria ficoides. Piece of a cast showing the appendages 

 attached. After Schimper in Zittel's Text-book, diagrammatically 

 represented. 



1 Schimper (1), t. 119, f. 8. a Heer (5), vol. 21, t. 12. 



* Steinhauer (1). 5 Lindley and Hutton (1), vol. i, tt. 32, 33, 36. 



7 Sternberg, Graf von (1), Heft 1-4, t. 12. * Zeiller (3), t. 173. 



10 Corda (1), t. 12. 



* Goldenberg (1), t. 13. 

 6 Corda (1), t. 12, f. I. 



Goldenberg (1), t. 13. 



