60 BRITISH OOLITIC AND LIASIC BRACHIOPODA. 



elevated striae, intersected by transverse lines, giving the whole surface a reticulated 

 appearance ; structure punctuated, and marked by well-defined lines of growth. 



Loop short, attached simply to crura, and not extending to half the length of the shell. 

 Length 12, width 11, depth 8 lines. 



Obs. As may be perceived from the list of synonyms here given, this species has 

 received three principal names, indiscriminately made use of by various authors ; however, 

 that of T. coarctata, established by Parkinson in 1811, appears the oldest and only one to 

 be retained, as T. reticulata of Smith and decussata of Lamarck, are of a later period. 



Mr. Sowerby, in 1823, proposed to retain both T. coarctata and T. reticulata, which he 

 thus characterises : — " Ter. coarctata subpentagonal, gibbous, hisped, and decussated ■ 

 lesser valves convex, subtrilobated j larger valve biplicated, with a deep angular sulcus 

 between the plaits. Ter. reticulata obovate, gibbose, subhisped, decussated, front obscurely 

 three-sided, with a shallow channel between the ridges." 



These distinctions are not sufficiently constant to authorise the proposed separation, but 

 are simple variations seen so usually in almost every species ; and in plate XIII we have 

 given illustrations of both varieties — fig. 12 representing Ter. coarctata, and fig. 15 

 T. reticulata, according to Mr. Sowerby ; fig. 15 also exhibits a very unusual form of beak 

 in this species, which is strongly recurved, with the foramen almost touching the umbo. 

 The general character of the beak is much less recurved. This species is likewise figured 

 by Mr.Walcot. 1 The surface, or spinose striaa ornamenting the surface, are very remarkable, 

 giving the shell a rough appearance ; and, as may be seen from the enlarged fragments 

 (fig. 14), these short and thick spines arise from under each other along the elevated ridge; 

 they are rarely preserved intact, but rubbed down so as to give the shell a striated appear- 

 ance : their hollow tubular character is noticed by Mr. Sowerby. We are indebted to 

 M. Deslongchamps for the interior, showing the loop, which is short in this species. 



Ter. coarctata is abundantly found in the Great Oolite, Forest Marble, and Bradford 

 Clay, all round Bath, Bradford, Hinton, Frome, &c, where it does not seem to exceed the 

 dimensions we have given : it is also a common species in beds of the same age on the 

 Continent, and especially round Caen, in Normandy. Fine specimens have, likewise, been 

 met with by M. Bouchard, near Boulogne-sur-mer. Mr. Walton informs me that he has 

 found this species in the Oxford Clay, but where it is very rare. 



58. Terebratula plicata, Buckman, 1845. Plate XII, figs. 1 — 5. 



Terebratula plicata, Buckman. 1845. Geol. of Cheltenham, pi. 7, fig. 6. (Non 



Ter. plicata, Lamarck, 1849. An. sans Vert., vol. vi, 

 No. 39, which belongs to another genus.) 



— — Tennant. 1847. A Stratigraphical List of British Fossils, p. 74. 



— subplicatella, D' Orb. 1849. Prodrome, vol. i, p. 287. 



1 Petrifactions found near Bath, No. 28. 



