TEREBRATULA. 57 



us perfectly worked out interiors of this shell. It attains considerable dimensions in some 

 localities ; the two largest specimens I am acquainted with are one in the British Museum, 

 and the other in the possession of M. Bouchard ; they resemble a billiard ball in form, mea- 

 suring 23 lines in length, 22 in breadth, and 21 in depth; our British specimens do not 

 attain these dimensions. In general, the convexity is regular from the umbo and beak to 

 the front ; but in some cases, after attaining certain dimensions, a temporary stoppage in 

 growth takes place, which, on being resumed, has caused the remaining portion of the shell 

 to deviate from the regular line, as in fig. 15. This is also the case in many specimens 

 which are smooth and regularly circular up to a certain period, but after a pause continue 

 their growth by giving birth to plaits or other ornaments, as we meet commonly m 

 T. fimbria plicata, &c. 



The lines of growth are likewise more or less prominent in different specimens. 



As stated by Sowerby, T. spharoidalis is found in the Inferior Oolite of Dundry, 

 Nunney, near Frome, in different parts of Somersetshire, in Normandy, Bayeux, Curcy, 

 Monstiers, St. Maixant, as well as in Germany, and at Allen, Stuifenberg, &c. 



54. Terebratula globulina, Bav. Plate XI, figs. 20, 21. 



Diagnosis. Shell inequivalve, globular, regularly convex, and gibbous ; beak small, 

 scarcely prominent, recurved, and truncated by a diminutive foramen almost touching the 

 umbo ; lateral ridges distinct, recurving to join the hinge line ; margin straight all round ; 

 valves almost equally convex, smooth, and punctated ; loop short, attached only to crura ; 

 length 2, breadth 2, depth 1 line. 



Obs. In 1847 I illustrated this small species, 1 but I did not at that period think it 

 prudent to distinguish it by a specific denomination, as we believed it might only turn out 

 to be the young of some species ; but from the great number of adult specimens found by 

 Mr. Moore, none of which exceed the dimensions above given, I have given to it the 

 name of globulina. It is found in the Upper Lias in the same bed that contains T. pygmea, 

 Lept. Moorei, liasiana, Bouchardii, &c, in the neighbourhood of Ilminster, and its dis- 

 covery is due to Mr. Moore. Fig. 20 natural size, fig. 21 enlarged. 



55, Terebratula pygmea, Morris. Plate XIII, 16, 16 a, b, c. 



Terebratula pygmea, Morris. 1847. Annals and Mag. of Nat. Hist., vol, xx, pi. xix, 

 fig. 3, a, b. 

 — — If Orb. 1849. Prodrome, vol. i, p. 221. 



Biagnosis. Shell inequivalved, of a somewhat hexagonal form ; valves convex, beak 



1 Annals and Mag. of Nat. Hist., vol. xx, pi. xix, fig. 4. 



