﻿CRETACEOUS BRACHIOPODA. 



45 



54. Terebratula Dallasii, Walker. Sup., PI. Ill, figs. 1 — 5. 



Terebratula Dallasii, Walker. Geol. Mag., vol. iv, p. 455, pi. xix, fig. 1, 1867 ; 



and vol. v, p. 404, 1868. 



Spec. Char. Shell ovate-globose, sometimes slightly pentagonal, longer than wide, 

 greatest breadth at about half its length ; both valves very deep, moderately convex to 

 about two thirds of their length, when they become suddenly bent downwards at right 

 or obtuse angles until they meet at the margin. Beak short, more or less incurved, and 

 truncated by a large foramen ; deltidium wide and narrow, in one piece. Surface smooth, 

 marked by concentric lines of growth. Loop simple and short. Two specimens 

 measured — 



Length 12, width 10, depth 12 lines. 

 „ 15, „ 10, „ 9 



Obs. This remarkable species was well described by Mr. Walker. Some examples 

 have attained to one inch and a half in length. It so closely simulates some thickened 

 specimens of Wald. tamarindus as to be almost mistakable for it, but may be at once 

 distinguished by the shortness of its loop. Internal casts show no evidence of the 

 existence of a septum in the smaller valve. The adductor muscular scars are large in 

 proportion to the shell. 



Position and Locality. T. Dallasii occurs, but not very abundantly, in the Lower 

 Greensand of Upware, and likewise in the Conglomerate bed near Potton, the latter 

 specimens being ferruginous. Mr. Meyer has some examples from the " Sponge-gravel " 

 of Earingdon, which he thinks may be referable to the species under description. 



55. Terebratula semiglobosa, Soto. Dav., Cret. Mon., PI. VIII, figs. 6 — 18. 



Terebratula semiglobosa, Tate. Quarterly Journal Geol. Soc, vol. xxi, p. 30, 1864. 



Some large globose specimens similar to those that occur in the Chloritic Chalk of 

 Mont St. Catherine, Rouen, have been found in the Lower Chalk of the Isle of Wight. 

 It has also been met with in great abundance in the Lower Grey Chalk or Limestone near 

 Belfast, and is not uncommon in the Red Chalk at Speeton and the Chloritic Marl of 

 Pinney Cliff and Beer. 



56. Var. Hibernica. Sup, PI. II, figs. 18—20. 



A large flattened variety (if not distinct species), intermediate in shape between 



