JURASSIC AND TRIASSIC BRACHIOPODA. 215 



prominent a manner as is the rule in the var. Smithii, and the ribs are more numerous 

 and smaller than in the var. socialis. The beak is very much incurved, so that the 

 foramen is almost entirely concealed. The largest example I have seen measured Sp- 

 lines in length, by about the same in breadth, and 6 in depth. 



Mr. E. Deslongchamps observes, in his description of this shell, that it so closely 

 resembles Bh. tetraedra from the Lias, that it might be taken for that shell ; but if one 

 examines a numerous suite of specimens, it is seen at once that var. spathica is much 

 closer to Bh. varians. 



In my paper on " An Examination of Lamarck's Species of Fossil Terebratulae," I 

 mentioned that Lamarck gives no reference to any figure, but states that his specimens 

 came from the hills on the boundary of the Sarthe ; and I was at a loss to know what is 

 the type of his species, not from want of specimens, but from the number of different 

 species placed under one head in the Lamarckian Collection. There were thirty speci- 

 mens, referable to Bh. tetraedra, Bh. concinna, Bh. varians, Bh. rimosa, and perhaps 

 another. 



Whatever may be the form intended by Lamarck, M. E. Deslongchamps figures, as 

 one of the types of Bh. spathica, a specimen from the lower portion of the Oxford Clay 

 of the Wast in the Boulonnais, and this agrees in every particular with those we find 

 in the Am. cordatus zone of the Oxford Clay at St. Ives, in Huntingdonshire, and in the 

 Kelloway Rock of Kelloway. Wald. impressa seems to accompany it in the same bed. 

 Eine examples have been collected by Mr. James Parker from the Oxford Clay of 

 Summertown, and St. Clements, Oxford ; and good examples may be seen in the Oxford 

 Museum. We will therefore consider this variety to represent the Bh. spathica and 

 retain the name. 



220. Var. Thurmanni, Voltz. Sup., PL XXVIII, figs. 14, 15, 16. 



Terebratula Thurmanni, Voltz. E. Thirria, Statistique Mineralogique et Geologique 



du Dept. de la Haute-Saone, pp. 172 and 179, 

 1833. 

 — — Brown. Lethsea Geog., p. 29, 1835. 



Rhynchonella Thurmanni, Etalon. Lethsea Brutrutaua, p. 291, pi. xlii, fig. 6, 1861. 

 — — J.F. Walker. Greol. Mag., 2nd ser., vol.ii, p. 572, 1875. 



This shell has been considered by Mr. J. F. Walker and some other jpalaeonto- 

 logists as a variety of Bh. varians, and as distinguishable from the var. Smithii 

 and var. spathica by its larger size and greater breadth when compared with its 

 length ; it is also less spherical than the variety spathica, to which, however, it approaches 



