SPIRIFERID. 87 
district). Linnzeus’s and Dalman’s specimens were obtained from the Island of Gothland ; 
and Herr Lindstrém states that it occurs in Mid-Gotland, at Klinteberg; Linde and 
Sandarfve Kullar; Lojsta; Stora och Lilla Carlsé ; Habblingbo, and Slite. 
SPIRIFERA PLICATELLA, var. RADIATA, Sow. PI. IX, figs. 1—6. 
DELTHYRIS LINEATUS (text), radiatus (Index), Sowerby. Min. Con., vol. v, p. 493, figs. 
1,2, May,1825. (Not Anomites lineatus 
of Martin.) 
SPIRIFER RADIATUS, J. de C. Sow. Silurian System, pl. xii, fig. 6, 1839. 
— _ M‘Coy. A Synopsis of the Silurian Fossils of Ireland, p. 37, 
1846. 
— cyRTENA, Dav. Bull. Soc. Géol. de France, 2nd series, vol. v, p. 
324, 1848. 
_ PLICATELLUS, Salter. Memoirs of the Geol. Survey of Great Britain, 
vol. ii, p. 382, 1848. 
_ RADIATUS, J. Hall. Pal. of New York, p. 66, pl. xxii, fig. 3; and p. 265, 
pl. liv, fig. 6, 1852. 
= PLICATELLUS, var. RADIATUS, Salter. Siluria, pl. ix, fig. 25; and pl. xxi, 
fig. 7, 1859. 
SPIRIFERA PLICATELLA, Lindstrém. Proceedings of the Royal Acad. of Sciences of 
Stockhoim, p. 358, 1860. 
Characters. More or less subtrigonal or rhomboidal, wider than long; valves 
moderately convex, beaks more or less approximate ; hinge-line straight, usually rather 
less than the width of the shell, wings or cardinal extremities more or less expanded, or 
by an outward curve meeting the hinge-line. Ventral valve rather deeper than the 
opposite one, with a rounded, more or less deepened mesial sinus, extending from the 
extremity of the beak to the front; beak incurved, area triangular, variable in breadth, 
fissure partly covered by a convex pseudo-deltidium. Dorsal valve convex, with a 
wide, moderately elevated, flattened mesial fold, sometimes depressed along the middle. 
Surface of valves generally evenly convex, or at times longitudinally divided by a few 
undulations, while the entire surface is covered with numerous fine, raised costs, and here 
and there a smaller interpolated rib ; between each pair of costz the interspace is concave 
and of smaller breadth, the whole surface being likewise closely crossed with fine, thread- 
like, raised, concentric lines. Two specimens measured— 
Length 15, width 24, depth 11 lines. 
3 13, ,, 16, Sowerby’s type. 
Oés. I greatly doubt Baron Von Buch being correct when he refers the species 
under description to Zerebratulites striatissimus of Schlotheim. The last-named shell 
was briefly described in the ‘ Petrefactenkunde,’ p. 252, 1820, with a reference for figure 
to the ‘ Taschenbuch fiir die gesammte Mineralogie,’ Tafel 1, fig. 7, 1813. The locality 
