Pleu 



ROKHTNCHUS. 



CONCHIFERA. 



201 



C. lobatum. Phillips, Geo. York, I. pi. 9, fig. 14. 



iV'early circular, oblique ; anterior side short, with a central 

 flexure, from whence it is finely rounded nearly to the beaks 

 on the opposite side ; surface smooth, with a few remote, 

 rather regular, indistinct lines of growth. 



The Coral Ra;r, Malton, Yorkshire. 



24. Caudum semi-olabbatum. — The Half-smooth Car- 

 dium, pi. LXXXII. fig. 12. 



C. semi-<jlabratum. Phillips, Geo. York, I. pi. 9, fig. 15. 

 Transversely ovate ; oblique ; posterior side smooth, a little 

 produced below; anteriorsidewith longitudinal divergent strise. 

 The Great Oolite, Cloughton Wyke, Yorkshire. 



25. Caiidicm i>XERTUii. — The Doubtful Cardium, jJ. 

 LXXXII. fig. 5. 



C incertum. Phillips, Geo. York, I. pi. 11. fig. 5. 



Slightly transverse ; anterior side short and rounded ; pos- 

 terior side large, rounded, and slightly concave above ; beaks 

 protruding ; surface smooth. 



The Inferior Oolite, Yorkshire. 



26. Cakdium SEMi-STRtATCM. — The Semi-striated Car- 

 dium, pi. LXXXII. fig. 9. 



C. gemi-striatulum. Deshayes, Coq. Foss. I. pi. 29, figs. 

 .9, 10. 



Elongated ; sub-triangular ; inflated ; anterior side short, 

 and gently curved ; posterior side concave ; surface with the 

 lower portion of the valves longitudinally striated, and a few 

 faint lines of growth ; base arcuated. 



The London Clay, Bracklesham. 



27. Cardicm Grcenlasdicum. — The Greenland Cardium, 

 pi. LXXXII. fig. 30. 



C. Grcenlandicum. Chemnitz, VI. pi. 19, fig. 198. 



Elongated ; a little pointed towards the beaks, which are 

 nearly central ; anteriorly curved ; posteriorly slightly con- 

 cave ; surface with many flattened longitudinal ribs, with nar- 

 row intervening furrows ; the whole crossed by narrow, flat, 

 circular laminae. 



The Red Crag, Bawdsey. 



28. Cardium cognatcm.— The Kindred Cardium, pi. 

 LXXXII. fig. 27. 



C. cognatum. Phillips, Geo. York, I. pi. 4, fig. 3. 



Nearly circular ; beaks central, much produced, and large ; 

 sides nearly alike ; surface smooth, with a few remote lines of 

 growth. 



The Great Oolite, Clonghton Wyke, Yorkshire. 



29. Cardium l^vigatum. — The Smooth Cardium, pi. 

 LXXXII. fig. 28. 



C. IcBciyatum. Brown, lUost. Recent Conch. Gt. Brit. p. 

 88, pi. 35, figs. 12-15. 



Elongated; sub-oval; somewhat oblique, and snb-com- 

 presscd ; narrowed towards the beaks, and expanded beneath ; 

 surface with many flat longitudinal ribs, divided by narrow, 

 shallow furrows ; the posterior side being destitnte of these ; 

 internal margin crenulated. 



The Pleistocene ilarine Formations, Largs and Stevenston, 

 Ayrshire. 



SO. Cardicm elongatum. — The Elongated Cardium, pi. 

 LXXXII. fig. 29. 



C. elongalum. Brown, lUust. Rec. Conch. Brit. p. 88, pi. 

 35, figs. 16, 17. 



Elongated ; oval ; a litttle oblique ; moderately inflated ; 

 with numerous flat ribs, and narrow intervening furrows, 

 crossed by very indistinct lines of growth ; internal margin 

 with crenulations all round. 



In the Pleistocene JIarine Formation, Portrush, Ireland. 



The former species and this are nearly allied ; but this is distinguished 

 by being narrower, more elongated, and more veutricose. 



Genus XXI V.— PLEU RORH YNCRUS.— Phillips. 



Shell transversely elongated ; hinge-line long, straight ; an- 

 terior side with a short prolongation ; posterior side length- 

 ened into an acute, wing-shaped, auricular process ; generally 

 longitudinally ribbed ; beaks but slightly produced. 



1. Pleurouiiy.nchus IIibeknicus. — The Irish Plcurorhyn- 

 chus, pi. LXXXII. fig.s. U, 15. 



P. Hibernicus. Phillips, Geo. York, II. p. 210, pi. 5, fig. 26. 

 Cardium Hihemicum. Sowerby, I. p. 187, pi. 82, figs. 1, 2, 

 and TI. p. 100, pi. 552, fig. 3. 



Deltoidal ; anterior side much produecil ; posterior side 

 greatly truncated, and in the form of a horse-hoof; bounded 

 by a large ridge, which encompasses its entire margin with a 

 nearly central produced wing ; beaks small, flat, and incurved ; 

 whole surfaced with numerous sharj) longitudinal ridges ; these 

 on the truncated or concave side coucentrical ; margins locked 

 together with sharp, serrated, small crenulations. 



The Carboniferous Limestone, Limerick, Mendip Hills and 

 Dovedale, Derbyshire. 



2. PLEiRORnyxcHus ARMATUs. — The Armed Pleurorhyn- 

 chus, pi. LXXXII. fig. 11. 



P. armatus. Phillips, Geo. York, II. p. 211, pi. 5, f. 29. 



Anteriorly gibbose ; slightly sub-truncate obliquely ; poste- 

 rior side with an elongated, slender, and acute wing ; surface 

 with longitudinal, flat, divergent ribs and furrows. 



The Carboniferous Limestone, Kildare, Ireland. 



3. PLEUROHHYxcors ALIFOR.MIS. — The Wing-shapcd Pleu- 

 rorhynchus, pi. LXXXII. figs. 24, 25. 



P. ali/'jrmis. Phillips, Pal. Fos. p. 34, pi. 17, fig. 51. 

 Cardium ahrforme, Sowerby, VI. p. 100, pi. 552, fig. 2. lb. 

 Geo. Tr. 2d Scr. V. pi. 56, tig. 2. Goldfuss, pi. 142, fig. 1. 



Sub-triangular ; anterior side convex, heart-shaped, 

 bounded by a carinated marginal ring ; posterior side wedge- 

 shaped ; beaks incurved ; surface with many pretty strong 

 longitudinal ribs. 



The Carboniferous Limestone, BoUand and Isle of Man ; 

 and the Devonian Rocks, Barton and Newton. 



4. PLECROBUY.Nxnus ELO.VGATUS. — The Elongated Pleuro- 

 rhynchus, pi. LXI.* figs. 29, 50. 



P. elonifaluf. Phillips, Geo. York, II. p. 211, pi. 5, fig. 

 28. Cardium elongalum, Sowerby, I. p. 1S8, pi. 82. fii'. 3. 

 Goldfuss, pi. 142, fig. 2. 



Transversely elongated ; ventricose; anterior side elongate"! 

 and conical ; posterior side very short, inflated beneath the 

 beaks ; surface with numerous fine, regular, longitudinal, radi- 

 ating stria;, which assume the form of ribs on the lengthened 

 side. 



Carboniferous Limestone, Bolland, Yorkshire, and Derby- 

 shire. 



2 u 



