﻿ACTING) PTERIA. 



71 



7. Actinopteria Wdrmii, F. A. Romec, sp. PI. VIII, figs. 2, 3, and 5. 



1843. Avicula Wurmii, F. A. Burner. Verst. Harzgeb., p. 21, pi. vi, fig. 7. 



1848. — clathrata, Bronn. Handbuch, pt. 3, p. 1052. 



1849. — Wurmii, d'Orbigny. Prodrome, vol. i, p. 85. 



? 1860. — trapeziformis, F. A. Riimer. Beitr., pt. 4, p. 161, pi. xxv, 



fig. 6. 



1881. — (Pterinea ?) normata, Barrande. Syst. Sil. Bohem., vol. vi, 



pi. cxxv, figs. 4 — 9 ; and pi. cxxii, 

 figs. 17—20, fit. F. 



L881. — — perdita, Barrande. Ibid., vol. vi, pi. cxxv, figs. 1 



—3, fit. F. 



1S84. Pterinea Wurmii, Clarke. Neues Jabrb. f. Min., Beil.-Band iii, p. 369. 

 1S84. Avicula Wurmii, Tschernyschew. Mein. Com. Geol. Kuss., vol. i, p. 3, 



pi. i, fig. U. 



? 1885. — Maurer. Abbandl. Grossb. Hessicb. Geol. Lands., 



Band i, pt. 2, p. 224, pi. ix, fig. 17. 

 1887. Actinopteria Wurmii, Tschernyscliew. Mem. Com. Geol. Buss., vol. iii, 



pt. 3, p. 43, pi. vii, figs. 15 a — c. 

 1889. Pterinea Wurmii, Whidbvrne. Geol. Mag., dec. 3, vol. vi, p. 78. 

 1891. Avicula Wurmii, Freeh. Abbandl. Geol. Specialk. Preuss., Band ix, 



pt. 3, p. 42, pi. iii, figs. 4 — 4 d. 



Description. — Left valve rather large and convex, oblique, very broad. Umbo 

 rather oblique and recurved, prominent, apparently extending slightly above the 

 hinge-line, and situated at its anterior end (excluding a small front wing). 

 Hinge-line straight, nearly the same length as the shell. Posterior wing large, 

 broad, undefined, triangular, slightly concave. Anterior margin long, oblique. 

 Inferior margin gently convex. Postero-inferior corner broadly rounded. 

 Posterior margin nearly perpendicular. External contour gently rounded, 

 steeper in front. Surface bearing rather numerous and very distant, low, 

 rounded, alternating rays crossed by occasional minute threads and by micro- 

 scopic transverse markings. Shell-structure very thin. 



Size of left valve. — About 25 mm. long, about 25 mm. broad, and about 

 7 mm. deep. 



Localities. — From Lummaton there are five specimens in my Collection ; and 

 from Wolborough a worn and doubtful example is in the Museum of Practical 

 Geology. A fragmentary specimen is in the Bristol Museum. 



Remarks. — As usual among these fossils the state of preservation of the 

 specimens renders their specific determination perplexing. They seem, however, 

 in their general shape and ornament to be distinguishable from the adjoining 



