Terebkatui.a. 



MOLLUSCA. 



141 



Lower Clialk, Ilamsey, Leeds, and Dorking, and tlio upper 

 Greensand, Wunuiuster and Blackdown. 



12-t. Terebratula plicatilis. — The Fine-plaiteJ Terc- 

 bratula, pi. LVI. fig. 51, 52, and G2, 63. 



T. />/initUls. Sowerbv, 11. p. 37, pi. 118, fig. 1 ; and T. 

 octoplicata, ib. fig. 2 ; Brongniart, Euv. Paris, pi. 4, fig. 

 5, 8. 



Gibbose, transversely obovate, length somewhat more than 

 its depth, wiilth about one-third greater than the length ; beak 

 rather short, and slightly incurved ; larger valve less inflated 

 than the other ; centre elevated by twelve obtuse plaits, with 

 fifteen or more on each side. Fig. 62 and 63, a variety dif- 

 fering from the other in being somewhat longer, and in having 

 from seven to nine plates only on the sinus. 



Upper Chalk, Graveseud and Norwich. 



125. Terebratula pleurodon. — The Side-toothed Tere- 

 bratula, pi. LVI. fig. 57 and pi. LVI.* fig. 2 to 7. 



T. pleunjilon. Phillips, 11. p. 222, pi. 12, fig. 16, 25, 26, 

 27, 28, 29, and 30. Ib. Pall. Foss. p. 86, pi, 35, fig. 155. 



Transversely ovate ; beak prominent ; hinge line arcuated ; 

 surface with large prominent ribs, emanating from the um- 

 bones, and terminating on the base ; the intermediate furrows 

 wide ; sides very deeply reflexo-dentate. 



The species is subject to much variety, and are thus defined by Pro- 

 fessor Phillips, viz. — 



a. The mesial portion elevated, large ; sides much refle.xed, with very 

 acute ribs, as iu tig. 



6. Rarkosta — The ribs few. 



c Polmioiita — Mesial ribs numerous ; margin squared. 



Fig. 57, pi. LVI. is a gigantic specimen. 



Carboniferous Limestone, Bolland, Orton, and Ireland ; 

 Devonian Limestone, Pilton and Petherwin. 



126. Terebratula angular;.?. — The Angular Terebra- 

 tula, pi. LVI. fig. 14, 15. 



T. antfularii. Phillips, Pal. Foss. p. 89. pi. 35, fig. 162. 

 Atrypa principilaris. Sowerby, Geo. Trans. 2d Scr. V. pi. 

 57, fig. 5, 6, and pi. LV.» fig. 61, 62, the young shell. 



Pentagonal, convex ; beak prominent ; front elevated, with 

 three or four plaits ; margin compressed ; a deep angular fur- 

 row emanates from the centre of the lower valve, and is 

 bounded by two angular ridges, terminating on the base. 



Devonian Limestone, Plymouth, Barton, and Eifel. 



127. Terebratula lateuali.s. — The Broad Terebratula, 

 pi. LVL* fig. 30. 



T. laterals. Sowerby, 1. p. 189, pi. 83, fig. 1. 



Semiovate, gibbose, its breadth exceeding its length ; beak 

 a little elevate<l and curved ; front greatly elevated in the 

 centre, with three ileep short plaits, producing three very deep 

 angular notches, filled by sharp teeth in the opposite valve ; 

 each side furnished with two plaits, which extend considerably 

 below the centre ; perforated or longer valve flatter than the 

 other ; there is a great length in the edge, between the central 

 ancl lateral plaits. 



Carboniferous Limestone, Cork, Irehind, and Bolland, York- 

 shire. 



128. Terebratula benifor.mis. — The Kidney -sliaped 

 Terebratula, pi. LVI. fig. 40, 55, 56, and 38, 39. 



T. rmlfurmU. Sowerby, V. p. 154, pi. 496, fig. 1, 2, 3, 4. 



Reniform, bilobatc, rounded, and inflated ; middle provided 



with three or four longitudiaal rounded ridges, terminated by 



acute plaits in the frontal margin ; sides inflated ; the ridges 

 and intermediate furrows are rounded ; the corresponding 

 notches iu the margin acutely angular. 



This shell is liable to considerable variety in the general contour and 

 in the number of its ridges. 



VtiiiETV 1. — Destitute of a mesial ridge. 



Variktv "2. — With from three to five obtase mesial ridges. 



ViRiETY 3. — From three to five acute mesial ridges.| 



Carboniferous Limestone, Dublin and Cork. 



129. Terebratula platyloba The Fiat-lobed Terebra- 

 tula, pi. LVL fig. 30 and 50. 



T. j)lati/lijha. Sowerby, V. p. 155, pi. 496, fig. 5, 6. 



Transversely ovate, considerably compressed, its width be- 

 ing nearly double its length ; umbo obtuse ; base witli seven 

 or eight rather obtuse ridges, which extend upw.ards two-thirds 

 the length of the valves ; several of the central ones somewhat 

 acute ; sides with one or two nearly obsolete plaits on their 

 edges. 



Carboniferous Limestone, Clithero. 



130. Terebratula borealis. — The Northern Terebra- 

 tula, pi. LVL fig. 26. 



T. hore<tlis. Schloth, Nac. pi. 20, fig. 6. T. pUcatella. 

 Dalmain, pi. 6, fig. 12. T. lacunosa. Sowerby, Sil. Syst. 

 p. eu, pi. 5, fig. 19. 



Obovate, gibbose, obscurely trilobate, and provided with 

 about sixteen acute longitudinal plaits, four or five of the 

 middle ones in front considerably more elevated than the 

 others ; beak small, acute, and slightly incurved. Length 

 seven lines, width eight lines. 



Devonian Shales, Ogwell and Plymouth ; Upper Ludlow 

 Limestone, Ludlow and Braubach, and the Wenlock Lime- 

 stone, TVeulock and Presteign. 



131. Terebratula chrysalis. — The Chrysalid Terebra- 

 tula, pi. LVI. fig. 60, 61. 



T. chri/salis, T. Gereillii. Woodward, pi. 6, fig. 14, Schloth, 

 M.G.S. Fr. pi. 16, fig. 9. Faugas, Mt. St., pi. 26, fig. 9. 



Oblong-ovate, sub-compressed ; beak extremely long, acute, 

 and slightly incurved ; hinge line of lesser valve straight, with 

 small auriform processes ; whole surface with pretty large 

 but not deep divergent ribs, producing a slightly creuulated 

 margin. 



Woodward supposes it possible that this may be the young of Triyo- 

 nuscimm lyta ; but it is totally distinct from that species. 



The Upper Chalk, Norwich. 



132. Terebratula flexistria. — The Waved Striate 

 Terebratula, pi. LVI. fig. 64, 65. 



T. flexistria. Phillips, II. p. 222, pi. 12, fig. 33, 34. 



Oblate, sub-depressed ; beak very small, hardly protruding 

 beyond the hinge line ; mesial elevation rounded ; lower valve 

 somewhat smaller and flatter than the other, with an incon- 

 spicuous beak ; sides considerably curved ; surface with many 

 floxous obtuse stri.'u or small ribs. 



Carboniferous Limestone, Bolland and Newton. 



133. Terebratula mesogonia. — The Interangular Tere- 

 bratula, pi. LVI. fig. 72, 73. 



T. int'sot/ona. Phillips, II. p. 222, pi. 12, fig. 10, II, 12. 

 Tetrahedral, frontal elevation single or cleft ; sides pro- 

 vided with one or two riba. 



Carboniferous Limestone, DoIlaDd. 



