96 DEVONIAN FAUNA. 



3. Myophoria teigona, F. A. Burner, sp. Plate X, figs. 9 — 11. 



1843. Thetis ? teigona, F. A. Homer. Verst. Harzgeb., p. 26, pi. vi, fig. 25, 



1856. — — Bronn. Jahrb., pp. 646, 651. 



1857. ScnizoDTJS tbigonus, Keferstein. Zeitsch. Deutsch. Geol. Gesell., vol. ix, 



p. 154, pi. iv, figs. 4, 5. 

 1884, — sp., Beushausen. Abhandl. Geo). Specialk. Preuss., Band vi, 



pt. 1, p. 97, pi. V, fig. 19. 

 1884. — FALLAX, Beushausen. Ibid., p. 98, pi, v, fig, 15 ? 



Description. — Shell rather large, equivalved, higher than long, subovate. 

 Umbo nearly central, prominent. Hinge large, much curved, with a large 

 triangular central tooth in the left valve fitted between two large teeth in the right 

 valve. Anterior margin long, moderately convex. Inferior margin short, 

 oblique, with nearly semicircular outline. Posterior margin similar to 

 anterior, but longer, and elbowed one-third way down. Contour gently and 

 nearly evenly convex, the greatest depth being not far from umbo. Pallial line 

 simple, some distance from margins. Anterior muscle-scar small, subcircular, 

 situate near the umbo. Posterior muscle-scar larger, situated rather above the 

 centre of the posterior margin. Interior of shell with a long, narrow, arching, 

 convex callosity, running from behind the umbo to the front of the posterior 

 muscle-scar. Surface apparently bearing a few growth-lines and numerous 

 indistinct concentric striae. Shell-structure very massive. 



Size. — A cast of the closed valves measures 14 mm. long by 18 mm. high, and 

 9 mm. deep. A large specimen is 32 mm. high by 23 mm. long. 



Localities. — In the Museum of Practical Geology are two specimens from 

 Richard's Summer-house, Croyde Bay, three from Baggy, and one from 

 " Barnstaple Road ;" in the Woodwardian Museum a specimen from Barnstaple, 

 and three poor specimens from west of Saunton Court ; and in the Porter 

 Collection two specimens on one slab from Pilton. 



Bemarhs. — These specimens, though generally poor and often squeezed com- 

 pletely out of shape, appear to indicate a well-characterised species, distinguished 

 by its narrow ovoid form, short arching hinge, large teeth, small obliquity, and 

 massive shell, and by the long spoon-like callosity. The best Woodwardian 

 specimen, which is a double cast, displays the clasping of the teeth in such a 

 way as to show that they were very large and strong ; and, as it appears to retain 

 its true shape, it shows that the shell was sometimes considerably higher than 



