﻿JURASSIC AND TRIASSIC BRACHIOPODA. 



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Terebratula punctata, T. sub-punctata, T. Edwardsii, and T. sub-ovoides. 



Mr. E. Deslongchamps justly remarks at p. 162 of his "Brachiopodes jurassiques" 

 that T. punctata, Sow., is very variable in shape, and that its characters are but slightly 

 marked. He adds that these are subject to considerable modification, for it merges 

 gradually into those so-termed species to which the names of T. sub-punctata, Dav. ; 

 T. Edwardsii, Dav.; T. Davidsoni, J. Plaime; T. BucJdi, Romer; T. Sinemtiriensis, 

 Oppel, have been applied. In the following observations we will restrict ourselves 

 to those forms which occur in Great Britain. 



This general view is, I believe, more or less reciprocated by Dr. D. Brauns, the Rev. 

 F. Smithe, Dr. Wright, aud U. Schloenbach, who have made these shells a special study, 

 and to whom I am indebted for many accurate observations and much useful material. 



I had already said at p. 18 of the Appendix to the first volume of my British 

 Fossil Brachiopoda, that I was ready to admit that T. sub-punctata is only the very adult 

 state of T. punctata, but that I was not yet prepared to say as much with reference to 

 T. Edwardsii. After fresh examination and comparison I am willing to admit that some 

 specimens of the last-named shell do gradually merge into T. punctata ; but it cannot be 

 denied that far the larger number of full-grown individuals differ to some extent from 

 Sowerby's species. Thus, for example, T. punctata is, in general, of an elegant oval 

 shape, with sides and front rounded, and with valves almost equally and moderately 

 convex ; while T. Edivardsii, on the contrary, is a less elongated shell, much more 

 massive or thickened, and usually nearly straight in front. 



It is therefore, at any rate, a sufficiently marked variety, and should consequently 

 retain its varietal denomination. Mr. E. Deslongchamps, indeed, although admitting 

 the close relationship of both T. sub-punctata and T. Edioardsii to T. punctata, has preferred 

 to retain them as separate species. 



Some uncertainty seems to have prevailed in the minds of several palaeontologists 

 with reference to T. sub-ovoides (Munster), Romer. It is quite evident that Romer's 

 figure of that shell (Sup., PI. XVI, fig. 11), published in the 'Die Versteinerungen des 

 norddeutschen Oolithen-Gebirges/ p. 5, PI. ii, fig. 9, 1836, entirely agrees with 

 Sowerby's T. punctata ; and the figure given by Oppel of T. sub-ovoides, in his ' Mittlere 

 Lias Schwabens/ pi. iv, fig. 1, seems as if drawn from a well-shaped example of 

 Sowerby's T. punctata (Sup., PI. xvi, fig. 12). In his ' Untere Jura in nordwestlichen 

 Deutschland,' 1871, Dr. D. Brauns describes T. punctata and T. sub-ovoides as distinct 

 species; but subsequently in his ' Obere Jura' (393), 1874, he alludes to the possible 

 identity of the two ; and in a letter dated May 4th, 1876, he informs me that he considers 

 T. punctata and T. sub-ovoides to belong to a single species. In corroboration of this 

 statement he sends typical examples of T. sub-ovoides from the Zone of A. Jamesoni from 



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