Description of the Fossils in the older Deposits of the Rhenish Provinces. 367 



The position of the spires in this species was not known, but we have ascertained that they are placed 

 as in the SpirifercB, that is to say, their opposite extremities are directed toward the lateral angles. In 

 the Terehratulce, as Von Buch observes, the ciliated arms are usually turned one toward the other, or 

 placed vertically in the shell and ending nearly in the middle of the ventral valve (^T. prised). 



Therefore this character of the position of the ciliated arms is not found exclusively in the Spirifer<E, 

 and we are already acquainted with three species of Terebratula in which it exists, T. concentrica, T. 

 Roissiji (Bull, de la Soc. Geol. de France, vol. xi. PI. III.), and T.ferita, de Buch (PI. XXXV. f. 3 b, of 

 this memoir). Besides which, the Spirifer bisulcatus, Sow., figured at the end of Prestwich's memoir 

 (Trans, of Geol. Soc. of Lond., vol. v. PI. XXXIX. f. 21.), has, on the contrary, its spires placed verti- 

 cally as in certain Terebratulce. The T. concentrica found at Nehou (La Manche) has a more distinct 

 fold to the ventral valve. It is also wider, which brings it nearer to the form of certain Spiriferce. 



Refrath, Eifel. Tchudova, Chimay, Huy, Couvin, Boulogne, Nehou. Newton, Torquay, Devonshire. 



2. Terebratula Voltzii, nob., Tab. nost., XXXV. f. 4, 4 a, 4 b. 



Shell rounded, inflated, valves equally gibbose, covered with very fine, regular, radiating striae from 

 sixty-five to seventy in number. These striae, before reaching the edge of the valves, combine in 

 bundles, by twos and threes, so as to form four or five obsolete folds in front. Beak of the dorsal 

 valve small, inflated and slightly recurved. Area triangular. Deltidium indistinct. Perforation 

 round, placed immediately under the point of the beak. Dorsal sinus very much raised. Ventral 

 valve more or less gibbose according to age. Varix slightly evident. Cardinal edges nearly rect- 

 angular. Lateral angles slightly curved. Width, 111 millim. ; length, 13; thickness, 10. 

 This species is distinguished from all those with which it might be confounded, by the extreme deli- 

 cacy of its striae. These latter, by combining together in the form of folds toward the edges of the 

 valves, bear some analogy to what is seen in T.furcillata and T. Schnurii. Young individuals are much 

 less ventricose, and they are subtrigonal. Theodori, see de Buch, Mem. Geol. Soc. France, PI. XIV. 

 f. 13, PI. XX.f. 12, p. 143. 

 Paff"rath ; rare. 



3. Terebratula Gryphus, de Buch, Mem. de la Soc. Geol. de France, iii. PI. XVI. f. 18. Uncites 



Gryphus, Defr. Diet. Sc. Nat., tome LVI. p. 257. Terebratulithes Gryphus, Schlot., Petref. p. 259., 



PI. XIX. f. 1 . Gypidia Gryphoides, Goldf. bei Dechen Handb. der Geogn. von De la Beche, s. 527. 



This shell is very common in the limestone beds of Paffrath and Hagen in Westphalia, where it is 



associated with Strygocephali and Megalodontes. Casts of the inside are also found in the grauwacke 



of Salchendorf, near Siegen. 



4. Terebratula cdiqua, nob., Tab. nost., XXXV. f. 1, 1 a, 1 J. 



Shell very elongated, elliptical. Valves equally ventricose, smooth, or only presenting striae of growth 

 which are not numerous. Beak of the dorsal valve inflated, very much recurved, and touching the 

 other valve. Aperture round and terminal. Area very small. Deltidium none. The dorsal valve 

 is inflated toward the middle, where it presents a sort of obsolete keel which soon disappears. 

 Ventral valve slightly keeled, attaining its greatest height at the middle, and forming a very regular 

 curve from the beak to the front. The latter is rounded, without any trace of fold or sinus. The 

 angle of the cardinal edges is 90°. These latter run into the lateral edges, which unite together in 

 front by a regular and continuous curve. Length, 59 millim. ; width, 38; thickness, 37. 

 This shell, shaped like a little canoe or caique, pretty nearly resembles the Terebratula lagenalis, 

 Schlotheim, which belongs to the middle oolitic beds. It diff'ers, nevertheless, in the angle of the car- 

 dinal edges, which is much greater, in the absence of the truncation in front, and in that of the three 



3 B 2 



