172 



CONOHIFERA. 



IVIODI 



anterior one small and terminal ; the mantle muscular im- 

 pression irre,i);ular, and destitute of a sinus. 



1 . MoDioLA SE.Mi-suLCATA. — The Semi-furrowed Modiola, 

 pi. LXXIL* fitr. 17. 



M. (?) scmi-sulcata. Murchison, Silur. Syst. pt. II. p. 617, 

 pi. 8, fig. 6. Cypricardia semi-sulcata. Phillips, Pal. Foss. pi. 

 17, fig. 57. 



Shell transversely ovate, convex, sub-bilobate ; anterior 

 considerably smaller than the other ; beaks prominent, 

 near the anterior extremity ; surface covered with transverse, 

 irregular, concentric furrows ; length one inch, wiilth two 

 inches. 



Found in the Lower Ludlow Rock at Shelderton Hill, and 

 near Aymestry. 



2. MoDioL.'i ANTIQUA. — The Ancient Modiola, pi. LXXIL* 

 fig. 8. 



M. antiqua. Jlurchison, Silur. Syst. pt. II. p. 628, pi. 13, 

 fig. 1. 



Shell obliquely ovate, somewhat convex, almost smooth, 

 with a few nearly obsolete concentric wrinkles ; anterior lobe 

 rather indistinct ; beaks small, placed near the anterior side ; 

 lentfth three-eighths of an inch, breadth six-eighths. 



Found in the Wenlock Shale, at Glass-House Hill, east 

 flank of May Hill. 



3. Modiola fuxata. — The Buried Modiola, pi. LXXI. 

 figs. 12, 13. 



M. arcuata. Williamson's MSS. 



Transversely oblong-ovate ; hinge-line arcuated ; beaks 

 very blunt ; surface with wrinkled lines of growth. 



Coal Shale, AVakefield. 



♦. Modiola Williamso.ni. — Williamson's Modiola, pi. 

 LXXI. figs. 24., 25. 



M. elonyala. ^Williamson's MSS. 



Much elongated transversely, narrow, compressed ; anterior 

 side short ; posterior side greatly elongated ; umbones de- 

 pressed and blunt ; surface with slightly wrinkled lines of 

 growth. 



The Coal Shale, Wakefield. 



5. Modiola depressa. — The Depressed Modiola, pi. 

 LXXIL fig. 41. 



M. depresna. Sowerby, I. p. 29, pi. 8, three upper figures. 



Ovate ; breadth nearly twice and a-ha!f its length ; greatly 

 depressed, and narrowing towards the posterior side ; margin 

 even and very regularly curved, much so at the anterior side ; 

 beaks rounded ; surface smooth and shining, and pearlaceous 

 within. 



The Lower Greensand, Atherfield, Isle of Wight. 



6. Modiola pallida. — The Pale Modiola, pi. LXXIL 

 fig. 40. 



M. pallida. Sowerby, I. p. 30, pi. 8, three right-hand 

 lower figures. 



Oblong; breadth about twice its length ; gibbose ; inferior 

 margin straight ; posterior side slisrhtly inflated ; beaki ob- 

 tuse ; surface smooth, and somewhat glossy. 



The Portland Stone, Fonthill and Brora. 



7. Modiola l.evis. — Tbe Smooth Modiola, pi. LXXIL 

 fig. 37. 



M. Icevis. Sowerby, I. p. 30, pi. 8, left-hand fiijure. 

 Sub-triangular; breadth not quite twice its length ; convex; 



posterior and lower margin nearly straight ; posterior side a 

 little produced, united by a short curve ; beaks small ; surface 

 very smooth ; tbe lines of growth nearly obsolete. 

 The Lias, Lyme Regis, near Weymouth, Dorsetshire. 



8. MoDioL.A ELEGANS. — The Elegant Modiola, pi. LXXIL 

 fig. 7. 



M. elegans. Sowerby, I. p. 31, pi. 9, left-band upper figure, 

 middle and lower figures. 



Oblong, gibbose ; breadth about twice its length, moderately 

 convex ; lower margin straight, dentated, with transverse 

 furrows ; posterior side inflated, with a few transverse furrows 

 near the base ; beaks slightly curved, and with fine, close, 

 slightly undulating striae, which pass over the most prominent 

 portion of the surface, and diverge over the anterior side to 

 the base, where they become obsolete ; interior frequently 

 pearlaceous. 



The London Clay, Bognor and Iligbgate. 



9. Modiola Aldami. — Aldam's Moiliola, pi. LXXIL f. 17. 

 M. aspera. (?) Var. Phillips, Geo. York, I. pi. 11, fig. 9. 

 Elongated; anterior side narrow; posterior side large and 



rounded ; hinge-line nearly straight and rather lengthened ; 

 umbones small and obtuse ; surface with numerous fine striae. 



The Inferior Oolite, Blue Wick, Glaizedale. 

 10. Modiola plicata. — The Plicated Modiola, pi. 

 LXXIL* fig. 1. 



M. plicata. Sowerby, p. 87, pi. 248, fig. 1. 



Much elongated transversely, its length about a fifth of its 

 width, a little curved ; anterior side separated by a ridge, above 

 which it is striated, the striae becoming gradually obsolete 

 towards the beak, where strong oblique plications commence 

 divergent from the beaks ; the other parts of the shell smooth ; 

 but with a few irregular lines of growth ; back almost straight ; 

 anterior side a little truncated, and the posterior obtuse. 



The Fuller's Earth, near Radstock, and the Inferior Oolite, 

 Cotswold Hill. 



11. Modiola imbricata. — The Imbricated Jlodiola, pi, 

 LXXIL fig. 36. 



M. imbricata. Sowerby, III. p. 21, pi. 212, fig. 13. 



Oval, elongated, its breadth twice its length ; front con- 

 cave ; anterior lobe forming a slightly elevated ridge, extend- 

 ing to the beak, which is angular ; surface with imbricated 

 ridges. 



The Lower Greensand, Pulborough, and the Cornbra.sh, 

 Felmersham. 



12. JMoDioLA Hillana. — Hill's Modiola, pi. LXXIL f. 8. 

 M. Hillana. Sowerby, III. p. 21, pi. 212, fig. 2. 

 Elongated ovate, its width a little more than twice its 



length, depressed ; posterior side narrow ; posterior lobe ob- 

 scure ; front a little concave ; back carinated, and tapering 

 towards the beaks, which are but slightly prominent ; surface 

 concentrically striated. 



The Fuller's Earth, Bathford Hill. 



13. Modiola aspera. — The Rough Modiola, pi. LXXIL 

 figs. 13, 14. 



M. aspera. Sowerby, III. p. 22, pi. 212, fig. 4. 



Ovate, transversely elongated ; length half its width ; pos- 

 terior side acute, very gibbose ; posterior lobe obscure, small, 

 and pointed ; surface with numerous transverse, elevated, rough 

 striae, which are strong towards the broader side of the shell, 



