PEEMS— PECOrTEKIDE.E— PECOPTElilS. 81 



the lower and middle portions, converging near tlie top to form the obtusely- 

 pointed apex; ultimate raehis strong, broadly canaliculate idaove, rounded 

 beneath, sparsely punctate; pinnules alternate, close, usually nearly con- 

 tiguous, often crowded, open, generally at or nearl)- at a right angle to the 

 racliis, ovate when small, becoming oblong, rounded at the apex, slightly 

 irregular, very slightly decurrent at the base, the small pinnules joined for 

 a little distance, with a decurring sinus, the large ones distinct to the base, 

 more or less constricted on the upper side of the base b)^ the decurrent 

 sinus, the largest ones frequently somewhat contracted in the inferior angle 

 also; lamina not very thick, dull, arched near the margin, and marked on 

 the ventral surface by a row of rather distant minute mannnillate points in 

 each interneural space; nervation coarse, generally distinct; median nerve 

 rather strong and but slighth' if at all decurrent in the large pinnules, 

 depressed slightly, minutely and irregularly lineate, passing nearly to the 

 apex of the pinnule, decurrent in the small pinnules; lateral nerves origi- 

 nating at a very oblique angle, curving at once outward, and forking near 

 the base, normally at a rather open angle, the upper division sometimes 

 forking again in the lower portion of the very large pinmdes, in passing 

 with slight upward curvature to the margin, which they reach at an angle 

 of 60°-75°; fructification unknown. 



In a portion of the specimen illustrated in PI. XXXVI, Figs. 1 and Ih, 

 the substance of the pinnules is so macerated that the rather coarse nerva- 

 tion stands out in relief. The conditions of preservation have also imparted 

 a rather greater degree of obliquity to the nerves in most of the pinnules 

 than is seen in those specimens in which the lamina is spread out more 

 evenly in tlie matrix. The punctations, which are quite distinct in the 

 rachises of the larger pinnse, are sparsely scattered in the fragment of a 

 smaller pinna seen in PI. XXXVI, Fig. 2. In one of the fragments sent by 

 Dr. Britts we have a segment of raehis 30 cm. in length, 10 mm. in width 

 at the base, and 8 mm. at the upper end, on which the upward-curved, 

 chaffy spines are as much as 3 mm. in length. This raehis is provided with 

 pinnaj a little larger than those seen in Fig. 1, or of nearly the size and 

 appearance of those shown in fig. 3, on pi. xiv, of Zeiller's Flora of the 

 Commentry Basin. Unfortunately this slab is not suited for photographic 

 illustration. The pinnules are generally not so close as in our Fig. 1. The 

 nerves, generally coarse and rather stift' in appearance, usually visible 



MON XSXTII C 



