36 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



Diagnosis. Shell inequivalved, subrhoraboidal short and broad ; when adult notched 

 and indented in front, perforated valve convex, beak slightly recurved, foramen separated 

 from the umbo by a deltidium in two pieces, front defined by two angles or emarginate 

 edge, imperforated valve flat or slightly convex, sometimes depressed longitudinally towards 

 the front ; smooth, punctuated and marked by strong lines of growth. Loop long, and 

 attached only to the Crura. Length 11, breadth 10, depth 6 lines. 



Obs. The above description agrees with that given by Mr. Sowerby; it is a very 

 variable shell : the flatness of the imperforated valve seems to be one of its principal 

 characters. Some specimens are however slightly convex ; it approaches near to T. carinata, 

 but is a shorter and wider shell, rarely presenting any of the longitudinal depression 

 common to Ter. resupinata and T. carinata, forming one of the transition shapes connecting 

 the resupinata tribe, with a depressed imperforated valve to those species in which the same 

 valve is convex, such as Ter. Waltonii. In PL IV, figs. 18, 19, 20, I have given the 

 original specimens figured in the ' M. C.,' kindly lent me by Mr. J. de C. Sowerby; fig. 21 

 belongs to Mr. Tennant's Collection, and shows an unusual deep longitudinal furrow. 

 This species belongs to the Inferior Oolite, and is stated to come from Nunney, near Frome. 

 Five specimens are preserved in the British Museum, collected by Mr. Cunnington. It 

 occurs also on the Continent, especially in Normandy, as noticed by M. Deslongchamps. 



30. Terebratula Waltonii, Dav. Plate V, figs. 1 — 3. 



Diagnosis. Shell inequivalved, more or less oval; valves convex, beak produced, 

 rounded, truncated by an entire foramen, separated from the umbo by a rather long deltidium 

 in two pieces ; lateral ridge of beak continued along the side, without recurving, to join 

 the hinge margin. The margin line of valves nearly straight all round; front and sides 

 emarginate ; surface smooth, finely punctuated ; very variable in form and dimensions : 

 with the same depth of 8 lines, the three specimens figured from the Collections of Messrs. 

 Walton and Tennant gave a length of 18, 18, 13, breadth 11, 13, 11 lines. 



Obs. This species is from the Inferior Oolite of Bath wick Hill, Bath and Burton. 

 The loop is unknown, but must have been simply attached to the Crura, and extended to 

 near the frontal margin. The emargination of most specimens of this species is very 

 remarkable, as well as the regular and almost equal convexity of the valves. It will take 

 place next to T. emarginata, to which it is most nearly allied. I name it after Mr. Walton, 

 of Bath, who has kindly afforded me frequent assistance in this work. 



31. Terebratula numismalis, Lamarck. Plate V, figs. 4 — 9. 



Var. Subnumismalis, Dav. Fig. 10. 



Terebratula numismalis, Lamarck. 1819. Anim., sans Vert., vol. vi, No. 22. 



— cor, Valenciennes in Lamarck, 1819, An. saus Vert., vol. vi, No. 22. 



