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DEVONIAN FAUNA. 



Giebel's, though without adopting his name. Giebel's original figure 1 is that of 

 a mere fragment, insufficient for unassisted identification ; but it distinctly differs 

 from our fossils, both in the size and the simple character of its ribs, and evidently, 

 if accurate, does not belong to the same species. 



Pterinea expulsa, Barrande, 2 seems a decidedly longer shell with simpler ribs. 



The original figure of Pterinea trimcata, F. Romer, 3 bears some slight resem- 

 blance to our fossils ; but, under the name of Gosseletia truncata, it is shown by 

 Freeh 4 to be entirely unlike them. 



Pterinea erinlta, F. A. Romer, is a much more circular and convex shell, with 

 a broader and less oblique anterior margin. It is placed by Freeh, 5 together 

 with Pt. striatocostata, under a new genus Myalinoptera among the Myalininse. 



In Avicula Mans, Waldsmidt, 6 the umbo is much more central and the shape 

 more circular. 



5. Genus. — Leiopteria, Hall, 1883. 



This genus or sub-genus is, in contour, median between Avicula and Gervillia, 

 and is distinguished from Actinopteria by its general shape, its sharp posterior 

 wing, and the absence of rays on both valves. It is covered by more or less 

 regular transverse folds or growth-lines ; and is quoted from the Devonian and 

 Carboniferous beds of Europe and America. 



It is very closely allied to Hall's other genus Leptodesma, which he distinguished 

 simply because its " anterior end is always nasute and acute instead of auriculate 

 and rounded." Freeh merges both of Hall's genera as " groups " or subdivisions 

 of the genus Avicula. 



De Koninck gives some forms of Streblopteria, M'Coy, which so nearly 

 approach the shell described below as to suggest generic identity. 



1. Leiopteria lingdlata, n. sp. PI. X, fig. 1. 



? 1S82. Pterinea, n. sp., Rolzapfel. Palaeontographica, vol. xxviii, p. 25S, pi. xlix, 



fig. 12. 



Description. — Left valve gently convex, transversely oval, slightly oblique, 

 with definite wings. Umbo minute, proximate, anterior, direct, acute, just 



1 1858, Giebel, 1 Silur. Faun. Unterharz,' p. 27, pi. v, tigs. 15, 18. 



- 1881, Barrande, ' Syst. Sil. Boheme,' vol. vi, pi. ccxviii, figs. 13, 14, Et. F. 



:; is 1 1, \\ Romer, ' lihein. Uebergaugsgeb.,' p. 78, pi. ii, figs. 1 a, b. 



1 I 891, Freeh, ' Abhandl. Geol. Specialk. Preuss.,' Band 9, pt. 3, p. 119, pi. xii, figs. 2—4. 



6 [bid., p. 137, pi. xi, tigs. 1—7. 



''' 1885, Waldsmidt, ' Zeitscli. Deutsch. Geol. Gesell., 1 vol. xxxvii, p. 924, pi. xl, figs. 4, 4 a. 



