LEPTiENA. 



MOLLUSCA. 



125 



Hemispherical ; hinge line equal in length to the diameter ; 

 margin regular ; lower valve regularly convex, but destitute of 

 a mesial furrow ; surface covered with u^iequally distributed, 

 slender spines, with elongated bases ; these are long, and in- 

 curved outwards on the hinge line. 



BoUand ; and South Petherwin, Devonshire. 



34. Lept^na lirata. — The Ridged Lepta;na, pi. LV. 

 fig. 5. 



Producta lirata. Phillips, Geo. York. II. p. 248, {fim- 

 briata, p. 215,) pi. 8, fig. 16. 



Suborbicular; umbo very large, and produced; hinge line the 

 entire widlh of the valves ; larger valve with longitudinal sulci, 

 and blunt ridges. 



Mountain Limestone, Moulton, and Isle of Man. 



35. Lept^na mesoloba The Middle-lobed Leptaena, 



pi. LV. fig. 15. 



Leptcena mesoloba? Phillips, Pal. Fos. p. 61, pi. 25, fig. 102. 

 Producta mesoloba, lb. Geo. York. II. p. 215, pi. 7, fig. 12, 13. 



Subovate ; hinge line the whole breadth of the valves, which 

 are wider than long ; auricles obtusely angled ; a mesial ridge 

 on the convex valve, with a corresponding furrow on the other; 

 surface smooth, or slightly wrinkled across. 



Mountain Limestone, BoUand ; Derbyshire ; and Codden 

 Hill, North Devonshire ; and Queen's County, Ireland. 



36. Lept-ena setosa. — The Bristled Leptsna, pi. LV. 

 fig. 17. 



Producta setosa. Phillips, Geo. York. II. p. 214, pi. 8, fig. 

 9 and 17. 



Semicircular ; hinge line parallel, extending the whole width 

 of the valves, prolonged into auriform processes ; front fre- 

 quently produced into a ridge ; surface with strong, longitudinal 

 strise, and very long, needle-shaped spines, set in quincunx 

 order. 



Mountain Limestone, Rokeby and Northumberland. 



37. Lept«na muricata The Muricated Leptsena, pi. 



LV. fig. 16. 



Producta muricata. Phillips, Geo. York. II. p. 214, pi. 8, 

 fig. 3. 



Nearly orbicular; umbo very large, and produced; hinge line 

 the width of the valves; back somewhat flattened; surface with 

 broad, strong, rounded, continuous ridges ; with regular, blunt 

 murications. 



Carboniferous Limestone, Kirby Lonsdale and Harelaw. 



38. Lept,ena sulcata The Furrowed Leptsena, pi. 



LIIL* fig. 20. 



Productus sulcatus. Sowerby, Min. Conch. IV. p. 17, pi. 

 319, fig. 2. 



Semicylindrical, short, very convex above, with a mesial 

 sulcus ; hinge line as wide as the valves ; whole surface with 

 strong, spinose, longitudinal ridges. 



Mountain Limestone, Derbyshire. 



39. LEPTiENA Pectinoidea The Pecten-shaped Lep- 



ta!na, pi. LIIL* fig. 22. 



Producta pectinoides. Phillips, Geo. York. II. p. 215, pi. 

 7, fig. 11. 



Orbicular ; hinge line not so wide as the valves, terminating 

 in distinct, auricular processes ; umbo large, and prominent ; 

 whole surface covered with numerous, pretty strong, smooth, 

 longitudinal ribs, which are furcated towards the base. 



Carboniferous Limestone, Bolland. 



40. Lept^na nodulosa — The Nodulous Leptaena, pi. 

 LIIL* fig. 21. 



Leptcena nodulosa. Phillips, Pal. Fos. p. 56, pi. 24, fig. 94. 



Somewhat semicircular, its width greatly exceeding its length; 

 lower valve concentrically and irregularly angulated, and some- 

 what nodulous near the border, where it is rectangularlv 

 reflected, and broadly undulated, its disk flat from the umbo 

 to the border; surface with irregular, interrupted, concentric 

 ridges and furrows ; whole shell with very fine and numerous, 

 close, flexuous, longitudinal striae. 



Devonian Limestone, Newton Bushel, and Hope, Torquay. 



41. Lept/ena Edelburgensis — The Addleburgh Lep- 

 tsena, pi. LIIL* fig. 27. 



Producta Edelburgensis. Phillips, Geo. York. II. p. 214, 

 pi. 7, fig. 5. 



Semicircular; hinge line nearly parallel, and very wide; beak 

 but slightly produced ; deeper valve evenly convex ; extreme 

 sides compressed; whole surface with coarse, longitudinal striae, 

 which is frequently duplicate ; spines few, or none. 



Nearly allied to L. latissima, but differs in its flattened ears. 



Carboniferous Limestone, Addlesburgh; Fountains' Fell; and 

 Bolland. 



42. Leptcena costata. — The Ribbed Leptaena, pi. LIIL* 

 fig. 15. 



Producta costata. Sowerby, Min. Conch. VI. p. 115, pi. 

 560, fig. 1. Phillips, Geo. York. IL p. 213, pi. 7, fig. 2. 



Transversely elongated; convex v^lve with a deep, triangular, 

 mesial furrow, and broad, rounded, longituilinal ribs, which are 

 decussated above by rather strong, concentric furrows, and 

 compressed at the base, which is deflected, the intervening 

 furrows narrow, and deep ; each side provided with two or three 

 spines, and a small lobe. 



Carboniferous Limestone, Glasgow; Bolland; Richmond, 

 Yorkshire ; and Hawes. 



43. Lept^na antiquata — The Antiquated Leptaena, pi. 

 LV. fig. 11. 



Productus antiquatus. Sowerby, Min. Conch. IV. p. 15, pi. 

 317, fig. I, 5, 6. PhiHips, Geo. York. IL p. 213, pi. 7, fig. 3. 

 Anomites semistriatus, Martin, Pet. Derb. pi. 32 and 33, fig. 

 1, 2, 3, 4. 



Semicylindrical, or quadrato-hemispherical ; hinge line some- 

 what shorter than the width of the shell, terminating in auriform 

 processes ; sides nearly parallel ; umbo extremely large, and 

 produced ; larger valve very much inflated ; lesser valve nearly 

 flat; mesial furrow wide; whole surface with rounded, radiating 

 ribs, reticulated at the umbo by concentric undulations, which 

 are larger, fewer, and more spinose towards the auricles. 



Young shells are plano-convex, with fine longitudinal and transverse 

 strise. 



Carboniferous Limestone, Bolland; Coverdale; Northumber- 

 land ; Derbyshire ; Flintshire ; and Kildare, Ireland. 



44. Leptjjna PUGILIS The Fighting Leptsna, pi. LIIL* 



fig. 13. 



Producta pugilis. Phillips, Geo. York. II. p. 215, pi. 8, 

 fig. 6. 



Semicircular; hinge line as wide as the shell, and terminating 

 in acute, spinous, auricular processes; umbo large, and much 

 produced; whole surface with numerous, equal, strong, radiating 

 2 I 



