333 



ORGANIC REMAINS. 



nitej with a central spiral columella, and a spirally decurrent 

 plate or valve within; aperture round, expanded; lip sharp 

 and entire 



Infundibulum rectum. F. 35. Conical, striated concentri- 

 cally j apex central, acute ; volutions obsolete ; valve rectangu- 

 lar; eolumella slender. Found at Holywell, near Ipswich. 



Pileopnt unguit. F. 59. Depressed, suborbicular, obscurely 

 radiated ; vertex recurved obliquely, acute, and extended be- 

 yond the base ; height about a third of its width. Found at 

 Holywell crags. 



PILEOI.US. Shell conical, with a sub-central vertex, placed 

 upright; base concave, centre tumid; margin thin; outer lip 

 prominent, interior lip crenulated, with a very short internal 

 tpire. 



Pileohu plicatiit. F. 40. The depressed cushion provided 

 with an elevated margin ; centre subdivided by a sulcus ; inner 

 lip deeply crenulated; height nearly equal to the diameter of 

 the base. Found in the oolite under the Bradford clay, at 

 Ancliff. F. 41 represents the internal structure. 



Emarginula cratsa. F. 48. Oval, very thick, obtusely 

 conical, furrowed, with four or five strife between each furrow ; 

 fissure wide. Found in the crag, near Ipswich. 



I'atella Itevis. Depressed, slender, conical, smooth, shining ; 

 aperture obovate ; apex eccentric; height about a third of its 

 length. Found in the alum clay at Whitby. 



CLASS VI. CONCHIFERA. 

 ORDER I. MONOMYARIA. 



FAMILY I. BRACHIOPODA. 



MAGUS. Bivalve, inequivalve, equilateral, one valve with an 

 angular sinus along an incurved beak ; line of the hinge and 

 back of the other valve straight, with two projections near the 

 middle. 



A partial longitudinal septum, with appendages attached to 

 the hinge within. 



Magus jmmiliis. F. KM. The beaked valve is smooth and 

 hemispherical, with a circular edge, beak small and incurved; 

 the other almost flat, with a lengthened transverse back. Found 

 In the chalk, near Marudesley, Norfolk. 



PENTAMERUS. Inequivalve, with the sides equal, one valve 

 divided into two parts by a longitudinal internal septum, the 

 other into three parts by two septa; beaks incurved and im- 

 perforate. 



Pentamenu Aybfordii. F. 165. Nearly orbicular, longitu- 

 dinally furrowed ; tripartite valve convex, with a prominent 

 incurved beak; bipartite valve gibbous, incurved, conical, with 

 8 greatly incurved beak. Found at Croft- Ambrey park. 



~Lingula mytittoides. F. 139. Beak indistinct, anterior, end 

 slightly truncated, somewhat depressed towards the front ; edi 

 nearly straight, of a greyish blue colour, with a shining sur- 

 face. Found in the dark-coloured limestone at Walsingham, 

 county of Durham. 



Spirifer cuxpidatus, F. 163. Inversely pyramidal, longitu- 

 dinally sulcated , back depressed, triangular, and equilateral; 

 front elevated by a semicircular sinus, corresponding to a large 

 longitudinal ridge, and depression in the under valve. Found 

 below St Vincent's rock, near Bristol. 



Terebratula concinna. F. 160. Almost globose, with very 

 sharp longitudinal ribs covering the whole shell, seven on the 

 elevated centre, and twelve or more on each side, regular ; 

 beak (f. 161) projecting. Found at Aynhoe. 



Terebratula ornithocephala, F. 147. Ovate, gibbous, front 

 straight, bounded by two obtuse lateral depressions, alike in 

 both valves ; perforation large, placed in the larger valve ; 

 breadth four-tilths of its length ; sides somewhat compressed, 

 producing an obtuse angular projection in front. Found in the 

 blue lias at Pickeridge. 



PRODUCTUS.s-Equilateral, valves unequal, margin more or 

 .ess cylindrical; hinge transverse linear; one valve convex, 

 the other flat or concave. 



Productits fpinulosus. F. 1G6. Semicircular, a little de- 

 pressed; hinge long and straight; convex valve gibbous to- 

 wards the beak, covered with numerous small spines with 

 indistinct ears; the other valve concave, and beeet with 

 numerous spines. Found in the limestone of Mid-Lothian, 

 Scotland. 



DIANCHORA. Bivalve, inequivalve; one valve, with an aper- 

 ture instead of a beak, by which the shell was attached to ma- 

 rine 'bodies ; the other valve provided with a beak and ears ; 

 hinge without teeth. 



Jjianchorditriata, F. 158. Somewhat spoon-shaped, oblique, 

 beak prominent ; free valve with a few obscure ribs at its base. 

 Found at Chute Farm, near Warminster. 



Ottrea Marthii. F. 122. Oblique, longer than wide, both 

 valves deeply plaited, with seven or eight angular divergent 

 rib-like undulations ; edge thick, flattened. Found in the vici- 

 nity of Felmershaw. 



HINNITM Du6i>on. F. 135. Bivalve, inequivalve sides nearly 

 equal, radiated; eared; area of the hinge quadrangular, tripli- 

 cate ; cartilage sunk in a deep longitudinal pit ; lateral portions 

 in which the ligament is placed striated ; sinus, for the recep- 

 tion of the byssiis, small ; muscular impression large, and con- 

 nected with indentations remaining for the attachment of the 

 mantle parallel to the margin of the valves. 



EXOGYRA. Inequivalve, unequal-sided, attached to other 

 bodies ; umboneg spirally curved to one side ; pit of the hinge 

 curved, nearly linear ; an obtuse tooth in the flat, free valve, 

 which fits into a cavity parallel with the hinge pit, in the con- 

 vex attached valve; each valve provided with one muscular 

 impression. 



Ejeogyrn conica, F. 137 and 138. Smooth, deep valve more 

 or less gibbous, curved, with an obtuse carination alone the 

 middle; flat valve suborbic-ular, with a greatly incurved, im- 

 pressed beak. Found at Folkstone. 



Sni p HA. Globular, with short, obtuse, incurved ears, with 

 one central and two remote teeth about the hinge, the line of 

 which is lengthened, slightly incurved, and terminating at one 

 end with an indistinct tooth, beneath the insertion of the ear ; 

 in its centre is a large, irregularly formed tooth, transversely 

 depressed, and pointing towards the incurved beak. 



Kphtcra corrugata. F. 154. Gibbous, ponderous ; surface 

 with coarse corrugations; rugie placed transversely and oli- 

 tusu, more conspicuous near the sides, nearly smooth in tiie 

 middle, but extends over the ears. Found in the iron Mind 

 formation, east of Sandown bay, Isle of Wight. 



Pecten guinguecostata. F. 129. Subtriangular, somewhat 

 oblique, semicircular, and toothed in front; convex valve rib- 

 bed and inflated, with six principal costae, and four intermediate 

 and lesser ones ; surface covered with fine transverse strife ; 

 upper valve flat and toothed. Found in the Sussex chalk, near 

 Lewes. 



Plagiostoma gigantea. F. 157. Depressed, and smooth, 

 deltoid, with the posterior side rounded into the front ; ears 

 small, anterior one longest, situated in a large, broad, and 

 straight furrow ; beaks pointed ; surface with obscurely diver- 

 gent strife. Found in the foetid limestone at Bath. 



Lima gibbosa, F. 145. Elongated, gibbous; ears not con- 

 spicuous ; centre of the valves with about eighteen divergent 

 striae, and smooth at the sides ; twice as long as wide. Found 

 in coarse limestone, in Cotswofd hills, Glamorganshire. 



IMOCBRHUB. luequivalve, free, longitudinal, and somewhat 

 inequilateral, hinge consisting of a callus, which supports the 

 ligament, at one end crenulated, above which is placed the 

 beaks. 



Inocermus sulcatus, .F. 152. Oblong, spatuliform, with 

 about nine longitudinal and strong ribs, which have much the 

 character of plaits of ostrea crista-galli; beaks prominent, one 

 of which is considerably incurved and acute. Found at Lewes. 

 GERVILLIA. Inequivalve, unequal-sided, oblique, greatly 

 elongated ; beaks placed near the anterior extremity ; hinge 

 long ; divided into several pits, and provided with many, more 

 or less lamelliform teeth; one muscular impression in each 

 valve. 



Gervillia avicutoides. F. 142 and 143. Obliquely lanceolate, 

 curved, and pointed at both extremities ; slope in which the 

 hinge is situated nearly half the length of the shell ; teeth of 

 the hinge few, and similarly disposed. Found in the Shanklin 

 sand. 



Pinna lanceolata. Greatly elongated, its length being four 

 times its breadth; lanceolate, slightly curved, longitudinally 

 striated, with a quadrangular section ; each valve divided into 

 two flat parts by a central line. Found in the ocheraceous 

 limestone, near Scarborough. 



PACHYMYA. Transversely elongated, very thick, subbilo- 

 bate, with the beaks near the posterior extremity. Ligament 

 partly immersed, and attached to prominent processes or fulcra. 

 Pachymya ffigas. F. 144. Shell thicker than long, slightly 

 curved with parallel edges ; posterior extremity small and 

 round, anterior somewhat truncated, close at both ends. Found 

 in the chalk at Lyme Regis. 



Chama haliotoidea, F. 133. Somewhat depressed, oval, 

 surface uneven, with an external longitudinal, curved, nearly 

 marginal line, and a deep, sunk, curved furrow inside the deep- 

 est valve, extending from the beak around the deep side, from 

 which it shelves to a flat surface, extending to the margin, 

 where it is broad, and slightly crenate within; muscular im- 

 pression large. Found in the green sand, parish of St Mary 

 Donhead, Wiltshire. 



Diseras arietina. F. 125. Somewhat heart-shaped, with 

 divergent beaks. 



Unto subconstrictus. F. 132. Ovate oblong, its length being 

 twice its breadth ; a constriction passing from the front of the 

 shell towards the beak on the anterior side, which is subtrun- 

 catcd. Found in Derbyshire. 



Trigonia striata. F. 162. Equivalve, inequilateral, trigo- 

 nal ; hinge with two divergent, elongated, compressed teeth, 

 transversely grooved on each side, and fitting into furrowed ca- 

 vities in the opposite valve. 



MEGALODON. Equivalve, longitudinal, accumulated towards 

 the beaks ; hinge provided with a long external ligament, a 

 large bifid tooth placed upon a septum, across the beak of the 

 right valve, and one irregular and one pointed tooth similarly 

 situate in the left valve ; a small pit near the teeth for the recep- 

 tion of the anterior ligament. 



Megalodon acu\eata. F. 140. Smooth, somewhat lanceo- 

 late, thick, with pointed incurved beaks; the surface uniformly 

 convex. Found in the limestone at Bradley, Devonshire. 



Pectunculus costatus. F. 130. Shell orbicular, depressed, 

 with twenty-five longitudinal, sharp ridges, and a few trans- 

 verse strife ; hinge provided with fourteen teeth ; margin cre- 

 nulated within. Found at Hordwell Cliff. 



AXINUS. Equivalve, transverse, and free; anterior side very 

 short; posterior side considerably produced, truncated, snd 

 with a lunette near the beaks ; hinge provided with a tang 

 oblique ligament, situated in a furrow. 



Axinus angutatus. F. 153. Subhexangular, posterior side 

 somewhat cuneiform, with a subcarination running from the 

 sides to the beaks ; posterior carination very obtuse. Found : u 

 the London clay, at Islington. 



HIPPODIUM. Equivalve, transverse ; valves inflated ; some- 

 what bilobed ; hinge with a single rugged tooth ; cartilage ex- 

 ternal. 



Tfippodium ponderos urn. F. 151. Thick, gibbous, and rue- 



