40 
BRITISH EOCENE FLORA. 
Helvet.' shows that the separation cannot he maintamed ; for in the drawings there are 
in places seven veins in L. helvetica to five in L. stiriaca ; while comparisons of the 
tracings of Heer's figures,^ here reproduced, shoAV that L. stiriaca is really the more 
strongly toothed. It is impossible, in fact, to compare the figure of L. stiriaca, vol. i, 
pi. viii, with that of Z. helvetica, vol, iii. pi. cxliii, fig. 2, without recognising that 
the latter is the upper part of the frond of the former. The species was founded upon 
Fig. 16.— X. helvetica. ' Flor. Tert. Fig. 17.— X. stiriaca. Ibid., vol. i. Fig. 18.— stir iaca (.'). ' Fl. foss. Arct.,' 
Helv.,' vol. lii, pi. cxliii, fig. 2 (part ). pi. viii, fig. 4. pi. xlv, fig. 7. 
insufficient material, and should have been annulled when the more perfect specimens 
were figured. Specimens of L. dalmatica which we have received present in like 
manner no distinguishing specific characters, and should not remain separated. 
In the ' Flora Fossilis Arctica,' p. 87, pi. xlv, fig. 7, we find a portion of a pinna 
figured under this name from Atanekerdluk, in Greenland. It possesses, however, 
according to Heer's description, only three ternary veins on each side of the pinnule; 
while in the description of the Swiss form six to seven were essential to the species, and 
YiG. I'd.— G. stiriaca. ' Flora of Ym. 20.— G. stiriaca. Ibid., fig. 13. Via. 2\.—G. stiriaca. Enlarged by 
Bovey,' pi. V, fig. 14 (part). Mr. Fitch. 
specimens possessing fewer are separated. He therefore seems to modify his specific 
characters to include it, and in modifying them thus, leaves them sufficiently open to 
1 Figure 16 shows the strongest denticiilation present in the drawing of the fine specimen of L. helce- 
tica in the third volume. , 
