50 SUPPLEMENT TO THE 



the name Mi/strophora Leioisii. Prof. Hall, however, had previously, in IS GO, proposed 

 the genus Bhenidium for 0. Lemisii^ and other similarly characterised species. The 

 median septum in Kayser's figure of the interior of Sic. Leioisii seems to be smaller than 

 in that of Sk. areola. In Orthis we do not find a similar septum. At Ferques, near 

 Boulogne-sur-Mer, we find another small species of Skenidimn, which has been described 

 and figured by M. E. Rigaux, with the name of Orthis Beshayesei (Bouchard), in the first 

 volume of the * Bulletin de la Societe Acadcmique de Boulogne,' 1872. 



Genus — Orthis, Dahnan, 1828. 

 45. Orthis Eifliensis, De Verneuil. Dav., Dev. Sup., PI. Ill, fig. 16, 16<x — e. 



Oethis Eifliensis, De Verneuil. Note Geologique surles Terrains de Sabero (Spain), 

 Bull. Soc. Geol. de France, 2nd ser., vol. vii, 

 1850. 



— — Schniir. Beschreibung sammtlicher im Uebergangsgebirge der 



Eifel-vorkommenden Brachiopoden ; Palseontograpbica 

 von W. Dunker und H. von Meyer, p. 213, pi. xxxvii, 

 fig. 6, 1853. 



— SACcuLus, F. Sandberger. Die Bracli. der Rheinischen Sch. in Nassau, 



pi. xxxiv, fig. 3, 1855, 



— Eifliensis, E. Rigaux. List of the Fossils found in the Lower Boulonuais, 



Geol. Mag., 2 ser., vol. v, p. 437, 18/8. 



Shell elliptical, as wide or a little wider than long, broadly rounded anteriorly, and 

 slightly indented in front. Hinge-line straight, less than the width of shell. Dorsal 

 valve very gently convex, and divided longitudinally by a median depression ; hinge- 

 area narrow. Ventral rather deeper than the dorsal valve, and longitudinally 

 divided by a mesial fold; beak incurved; area triangular, half a line in breadth, and 

 divided by a triangular open fissure. Surface of both valves finely radiately striated 

 with one, two, or three shorter and smaller ribs interpolated between the larger ones. 

 Interior not known. 



Length 5, width 6, depth 2 lines. 



Obs. — The proportions above given are taken from the largest English specimen that 

 has come under my notice. Schnur figures an Eifel specimen as measuring 7 lines 

 in length by the same in breadth. I picked up a finely-preserved specimen in the 

 " Beaulieu shales " or Upper Devonian at Ferques, measuring 7 lines in length by 8 in 

 breath and 3^ in depth. 



