﻿ACTINOPTERIA. 



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decidedly finer, and that its shape is generally more transverse. I therefore have 

 followed him in not uniting it at present. 



Actinopteria Boydii, Conrad, sp., 1 has more or less foliaceous transverse strise, 

 and its front wing is rather larger. 



Under the name Avicula semiliana, Freeh 2 separates from A. Wurmii a shell 

 which he chiefly distinguishes by its rather finer strise and its rather larger front 

 ear. Thus it tends in the direction of A. dilatata, but its distinctions from 

 A. Wurmii are so slight as to be in my view scarcely specific ; especially when 

 the variability of these shells is taken into account. As the anterior wings of our 

 specimens are unknown, no comparison can be made in that direction ; their 

 ribbing seems to agree rather better with that of Romer's shell. 



Limoptera Bohemica, Barrois, 3 which is Avicula Bohemica, Barrande, 4 has much 

 more definite threads which reticulate the rays. 



Actinopteria theta, Hall, 6 which is regarded as a synonym of the present species 

 by Tschernyschew, is much more finely ribbed. 



8. Actinopteria rudis, Phillips, sp. ? PI. VIII, figs. -A and 6, 6 a. 



1841. Avicula rudis, Phillips. Pal. Toss., p. 50, pi. xxii, figs. 85 a, b. 



1848. — — Bronn. Haudbuch, pt. 3, p. 141. 



1849. — — d'Orbigny. Prodrome, vol. i, p. 84. 

 1854. — — Morris. Catal. Brit. Foss., p. 162. 



? 1860. — semiglobosa, F. A. Bonier. Beitr., pt. 4, p. 161, pi. xxv, fig. 8. 



1880. Ptebinea Morleti, CElrfert and Davoust. Bull. Soc. Geol. Fr., ser. 3 



vol. vii, p. 715, pi. xv, fig. 9. 



1888. — rudis, Mheridge. Foss. Brit., vol. i, Pal., p. 159. 



Iss!) — — Whidborne. Geol. Mag., dec. 3, vol. vi, p. 78. 



Description— -Left valve rather small, convex, broader than long, slightly 

 oblique. Umbo large, prominent, rounded, proximate, apparently extending 

 slightly above the hinge-line, and situated at about the anterior third of its length 

 (including the anterior wing). Anterior wing rather large, long, trapezoidal, 

 perpendicularly convex, and defined. Posterior wing large, very broad, flattish, 

 and defined. Hinge-line straight, nearly as long as the shell. Anterior margin 



1 1842, Conrad, ' Journ. Acad. Nat. Sci. Philad.,' vol. viii, p. 237, pi. xii, fig. 4 ; and 1884, Hall, 

 'Pal. N. Y.,' vol. v, pt. 1, p. 113, pi. xix, figs. 2—24, 26—30; and pi. lxxxiv, figs. 16, 17. 



2 1891, Freeh, ' Abhandl. Geol. Specialk. Preuss.,' Band xi, pt. 3, pi. lii, figs. 1—1 b. 



3 1889, Barrois, 1 Faun. Calc. d'Erbray,' p. 173, pi. x, figs. 9—9 6. 



* 1881, Barrande, ' Syst. Sil. Bohein.,' vol. vi, pi. ccxix, fig. 7, 1-3; and pi. ccxxii, fig. 1, n-ic. 

 Et. F. 



5 1884, Hall. ' Pal. N. T.,' vol. v, pt. 1, p. 125, pi. lxxxiv, figs. 18, 19. 

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