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SUPPLEMENT TO THE BRITISH 



the front. Surface smooth, marked by concentric lines of growth. Proportions variable; 

 two specimens measured — 



Length 14; width 9; depth 9 lines. Length 10; width 7; depth 6 lines. 

 Obs. — This seems a tolerably marked variety ; it differs from T. punctata proper by 

 its large strongly incurved beak and very small foramen, also by the greater convexity of 

 its valves, and by a depression in the front line, which in T. punctata is either straight or 

 slightly convex. It is the shell alluded to by Mr. E. B. Tawney in his paper on the 

 Lias of the neighbourhood of Radstock (' Proceedings of the Bristol Naturalists' Society,' 

 vol. i, p. 187, 1874), in which it is said — "We may cite as characteristic of our 

 Middle Lias a form which we take to be T. sub-ovoides (Romer). It is so constant in its 

 form that it seems perhaps entitled to the rank of a distinct species ; it is more elegant 

 than T. punctata, but I am by no means sure that it has not been included by Mr. 

 Davidson under that species." This form seems to agree pretty nearly with some 

 specimens of the shell described by Mr. E. Deslongchamps at p. 154, pi. xxxvii, fig. 4, 

 and pi. xxxviii, figs. 1 — 8 of his " Brachiopodes jurassiques" as T. sub-ovoides, Romer, an 

 identification he now admits to be erroneous. It is stated by Mr. Tawney to occur in the 

 Middle Lias at Huish Quarry, near Radstock, where it appears to be rather abundant. 

 Perhaps figs. 9 and 10 are referable to the variety under description. 



95. Var. Havesfieldensis. Sup., PI. XVI, figs. 3, 4, 5. 



Shell broadly oval, valves moderately and regularly convex, slightly depressed near 

 the front ; beak incurved and truncated by a moderately large foramen ; beak-ridges 

 sharply defined, surface smooth. 



Length 1 inch 10 lines; width 1 inch 7 lines; depth 1 inch. 



Obs. — This is the shell which Messrs. Etheridge and Walker thought, perhaps rightly, 

 might be a variety of T. trilineata, and proposed for it the designation of sub-trilineata, 

 It occurs in the same bed with T. punctata, and so much resembles specimens of 

 the last-named species that I have preferred to leave it among the varieties of Sowerby's 

 species. It proves the close connection between T. trilineata and T. punctata. It 

 occurs in the Upper Lias Sand (Midford Sands) at Frocester and Havesfield Beacon 

 in Gloucestershire, from which locality specimens have been sent me by the two 

 gentlemen above named, as well as by the Rev. F. Smithe, of Churchdown. Some good 

 examples may likewise be seen in the Museum of the School of Mines. It also agrees 

 with some specimens of T. sub-punclata figured by Mr. E. Deslongchamps in PI. xxxix of 

 his "Brachiopodes jurassiques." 



