﻿JURASSIC AND TRIASSTC BRACHIOPODA. 



143 



foramen, separated from the hinge-line by a narrow deltidium. Surface smooth. Loop 

 not known. Dimensions half a line in length by a little less in breadth. 



05s. This is an exceedingly minute shell, and might be the young stage or fry of 

 some other described species. I have seen seven specimens which were all alike and of 

 the same dimensions. The drawings of this shell published in * The Geologist ' are not 

 quite correct, as the depression dividing the smaller valve is not represented. The 

 interior of the dorsal valve was not complete, but it exhibits a longitudinal central 

 ridge. This minute species (?) was found by Mr. C. Moore in the Great Oolite of 

 Hampton Cliff, Bath. 



]18. Terebratula coarctata, Parkinson. Dav., Ool. Mon., p. 59, PI. XII, figs. 12 — 



14 ; and Sup., PI. XIV, figs. 18, 1 ( J. 



Subsequent to the publication of my description of T. coarctata and T. reticulata 

 (Smith) as a single species, in 1851, much difference in opinion has been expressed 

 with reference to the above combination. Some palaeontologists would follow the view I 

 then expressed; others would maintain T. reticulata as a named variety of coarctata; 

 while some would consider it a distinct species, and especially the shell described and 

 figured by Sowerby as T. reticulata ? Smith. Sowerby was evidently not certain that 

 his T. reticulata was the same as that of Smith, for he places a note of interrogation 

 after the name and before that of Smith. 



In the fourteenth volume of the second series of the ' Bulletin of the Geological 

 Society of France' (1856), Mr. Kcechlin-Schlumberger, when treating of T. coarctata 

 (Park.), T. reticulata (Smith or Sow.), and T. Richardiana (d'Orb.), enters upon an 

 elaborate review of the whole question, and concludes that the two first named should be 

 referred to the same species. Bronn follows Morris and suppresses T. reticulata. 

 Much stress is laid by some palaeontologists on the statement that Smith's T. reticulata 

 is more elongated in shape, showing scarcely any fold, and that the reticulation of the 

 surface is much finer than in Parkinson's species, and also upon the fact that the 

 geological horizon is different. 



If we examine Smith's figure of T. reticulata in the plate facing page 30 of his 

 'Strata Identified by Organic Fossils,' 1816, we find that in essential characters it 

 agrees with T. coarctata ; it is not an elongated, but a broad pentagonal shell, with 

 well-defined mesial fold, and it is stated to occur in the clay over the Upper Oolite, 

 whence Sowerby states T. coarctata comes. Palaeontologists would therefore, I think, 

 be justified in considering Smith's T. reticulata a synonym of coarctata. 



If the form called T. reticulata ? by Sowerby, and occurring in the Inferior Oolite of 



