77 



inch in breadth, and about the same in depth. It is sub-pent- 

 agonal, slightly longer than wide, and, posteriorly, almost gib- 

 bous. There exists in the smaller valve two rounded folds, situ- 

 ated near the front, and rather close together, but separated by a 

 narrow sulcus. The beak is large, closely curved over that of 

 the opposite valve, and truncated by a small circular foramen. 



No. 7. TEEEBEATULA SPHOIEOIDALIS, Sow. Plate II., fig. 6. 



TEEEBEATULA SPEKEKOIDALIS, Sow. Min. Con., vol. v., p. 49, tab. 

 435, fig. 3, 1823. 



This shell is almost circular, spheroidal, and uniformly convex. 

 Some specimens from Bradford Abbas measure fourteen lines 

 in length by thirteen in breadth and twelve in depth. In 

 other places, and especially upon the Continent, they have some- 

 times attained to nearly the dimensions of a billiard ball. The 

 beak is much incurved, and the foramen small. 



No. 8. TEEEBEATULA DECIPIENS, E. DesL Plate II., fig, 1, and 

 Plate III., fig. 3. 



TEEEBEATULA DECIPIENS, E. DesL BracMopodes Jurassiques, 

 p. 285, pi. 83, 1873. 



Shell oval, longer than wide, smooth ; valves uniformly 

 convex, without fold or sinus, front line nearly straight or slightly 

 bisinuated ; beak closely incurved over the umbone of the 

 smaller valve, and truncated by an oval-shaped foramen. Two 

 specimens measured the first, two inches four lines in length, 

 one inch nine lines in width, and one inch seven lines in depth ; 

 the second, one inch four lines in length, one inch two lines in 

 width, and eleven lines in depth. This species is very nearly 

 allied to Ter. splicer oidalis ; but, according to Mr. E. Deslong- 

 champs, is distinguishable by its greater length, compared with 

 its width, and lesser degree of convexity. The specimens from 

 Bradford Abbas and Crewkerne Station were identified by Mr. 

 Deslongchamps as full-grown examples of his species, and finer 

 than any he had found in France. It varies considerably in 

 shape, and in the convexity of its valves. 



