13 



The nerves of the leaflets of this species, are describ- 

 ed by all the above mentioned authors as simple and 

 nearly at right angles to the midrib ; • — whereas these 

 nerves of our fossil impression , Avhich consists of two 

 detached pinnae, are, as already observed, discovered 

 to be dichotomous, while their direction agrees with 

 that always attributed to the species. 



It seems barely expedient to base the specific inde- 

 pendence of this fossil plant upon this single disparity : 



— we choose, rather, to leave the case as it stands, — 

 subject to future correction. The author feels himself 

 justified, however, in expressing his opinion that the 

 furcation of the nerves has hitherto escaped observation, 



— inasmuch as it was detected in the present case, only 

 through the aid of quite a powerful lens; while the 

 fossil impression is very distinctly defined. 



Distribution, in coal formation: — at Alais (?), 

 France; in Pennsylvania. 



HEMITELITES TREVIRANI , GO PP. 

 PI. I, fig. 4. 



GU2ip. Syst. fil. foss. ;a 233, _^j/. 38, /</«. 3, 4. 

 Unyer , Gen. et Spec. p. 161. 



PEC.OPTERIS TREVIRANI, 



Sternh. Vers. I , ^>. 158. 



Frond bipinnate; petiole channeled, strong and not 

 attenuate; leaflets long, sub-ovate, adjacent at the base 

 and situate obliquely to the common petiole; midrib 

 distinct and extending to the apex of the leaflet ; nerves 

 right angular to the midrib. The leaflets bear traces 



1 "Nervis secundariis tenuissimis e nervo medio angulo recto 

 exeuntibus subsimplicibus." 



