638 CAMBRIAN BRACHIOPODA. 



advance of the centrals, close to the median ridge and smaller than the centrals; the main 

 vascular sinuses are very faint beyond where they come forward into the body of the valve; 

 back toward the posterolateral margin of the valve small cardinal scars occur at about the same 

 distance from the center of the area as the central scars are in front of it. 



Observations. — This species is so strongly marked in its ventral valve by the pointed tuber- 

 cles beside the apex, the cone-shaped pedicle passage through the shell, and distinct visceral 

 area, and in the dorsal valve by a well-defined area and small cardinal muscle scars far out 

 on the cardinal slope, that it can not readily be confused with any known species. 



Formation and locality. — Middle Cambrian: (94x) Shales 0.06 mile (0.1 km.) soutli of Givens Mill, Cowan 

 Creek, about 8 miles (12.8 km.) southeast of Center; and (90x) in and attached to the outer surface of siliceous nodules 

 in the Conasauga ("Coosa") shale, Coosa Valley, east of Center; both in Cherokee County, Alabama. 



ACROTHELE BEEGEEONI Walcott. 

 Plate LVIII, figures 6, 6a-c. 



La Disdna Miqxtel, 1893, Note sur la G6ologie des Terrains Primaires du D^partement de I'H^rault, St. Chinian h, 



Coulouma, p. 9. (Mentioned in French.) 

 'La Biscina Miquel, 1894, Bull. See. d'Etude Sci. Nat. B^ziers for 1893, M6m. Compt. Rend, des Stances, vol. 16, 



1894, p. 106. (This article is a copy of the preceding reference which was published as a separate.) 



La Disdna Miquel, 1894, Note sur la Geologie des Terrains Primaires du D^partement de I'H&ault, le Cambrian et 



I'Arenig, p. 10. (Mentioned in French.) 

 La Disdna Miquel, 1895, Bull. Soc. d'Etude Sci. Nat. Bfeiers for 1894, M^m. Compt. Rend, des Seances, vol. 17, 



1895, p. 10. (This article is a copy of the preceding reference which was published as a separate.) 

 Acrothele Pompeckj (in part), 1896, Jahrb. K.-k. geol. Reichsanstalt for 1895, Bd. 45, Hft. 3, p. 603. (Discussed in 



German, changing generic reference; see under Botsfordia ? barrandei, p. 603, for copy.) 

 Acrothele bergeroni Walcott, 1908, Smithsonian Misc. Coll., vol. 53, No. 3, pp. 83-84, PL VIII, fig. 11. (Described 

 and discussed as below as a new species. Fig. 11 is copied in this monograph, PI. LVIII, fig. 6c.) 



All the specimens representing this species are flattened by compression in the argillaceous 

 shale, also more or less distorted. The outline of figure 6 (PL LVIII) is probably the nearest 

 the original outline of the ventral valve, and figure 6c of the dorsal. A ventral valve 6 mm. 

 in length has the apex 1.5 mm. from the posterior margin. A cast of the interior of a ventral 

 valve (PL LVIII, fig. 6b) indicates a relatively large interior opening for the pedicle tube; 

 a short, small visceral cavity with the shell thickened so as to form a short ridge; and an obscure 

 false area; also that the posterior margin is arched sHghtly above the plane of the margin of 

 the valve. An exterior cast shows the impression of a minute elongate tubercle on each side 

 of the apex, and a small pedicle opening just back of them. A cast of the interior of a dorsal 

 valve shows a short median ridge, and the posterior portion of the main vascular sinuses. 



The exterior cast shows that the surface was marked by small concentric ridges and lines 

 of growth, a few low, obscure, rounded, radiating ridges, and fine granulations or tubercles 

 on very minute, irregular, more or less inosculating concentric ridges, or the same type of 

 surface as that of Acrothele coriacea Linnarsson. If these shells were found at the same horizon 

 in Sweden as A. coriacea I think they would be referred to that species except that the apex 

 of the ventral valve of the French species is much nearer the posterior margin; more perfect 

 specimens would probably show other differences. 



This species appears to differ from Acrothele quadrilineata Pompeckj and A. iohemica 

 (Barrande) by the more anterior position of the apex of the ventral valve. 



In response to a request for permission to study the Cambrian brachiopods that he had 

 collected from Montague Noire, Mr. Miquel very courteously sent me a number, and among 

 them I found this species, and, with his permission, have described it. 



It gives me pleasure to give the specific name in recognition of the discovery by Prof. J. 

 Bergeron of the Middle Cambrian fauna of Herault, and his fine work on the fauna. 



Formation and LOCALrry. — Middle Cambrian: (343 [Miquel, 1893, p. 9]) Shales in Montague Noire, Coulouma, 

 Department of Herault, France. 



