108 



MOLLUSCA. 



Spirifer. 



Section I Ccspidata — Beaks imperforate, sepa- 

 rated by a triangular area, the lower one not incurved ; 

 upper valve convex ; hinge line generally straight, and 

 equal to the breadth of the shell. 



1. Spirifer cuspidatus The Pointed Spirifer, pi. 



XLIX. fig. 25, 36, 37, 38. 



Spirifer cuspidatus. Sowerby, II. p. 42, pi. 120. lb. V. p. 

 90, pi. 461, fig. 2. Fleming, p. 371. Brown, Ells. Foss. Conch, 

 p. 71, pi. 7, fig. 8. Anomia cuspidata, Martin, Linn. Trans. 

 IV. p. 45, pi. 3, and pi. 4, fig. 5. lb. Pet. Derb. pi. 46 and 47, 

 fig. 3, 4, 5. 



Shell inversely pyramidal, longitudinally sulcated ; deeper 

 valve nearly flat on the back, triangular, and equilateral ; beak 

 very slightly incurved, or straight in some specimens, and in 

 some instances recurved; depth equal to its greatest width, 

 which is occupied by the hinge line ; front elevated by a semi- 

 circular sinus, corresponding to a produced, longitudinal ridge, 

 and depression in the lower valve ; opposite valve about one- 

 third the depth of the other, its length being about equal to 

 one-half its width ; margin semicircular ; on each side of the 

 smooth, central undulation, it is provided with about fifteen 

 sulci; surface marked vkith a few lines of growth, and continuing 

 over the beak, which is covered with fine, longitudinal stria; ; 

 foramen with reflected edges. 



Found in the Carboniferous Limestone of Derbyshire; Gla- 

 morgansliire ; near Cork, and also near Dublin, Ireland. 



2. Spirifer insculpta The Carved Spirifer, pi. XLIX. 



fig. 29, 30. 



Spirifera inscidpta. Phillips, II. p. 216, pi. 9, fig. 2, 3. 



Cardinal area very wide, with the mesial and two or three 

 lateral folds very large, triangular and deep, acute at the edges, 

 and with wide-set, transverse strias. 



Mountain Limestone, BoUand, Derbyshire. 



3. Spirifer senilis The Aged Spirifer, pi. XLIX. 



fig. 29. 



Spirifera senilis. Phillips, II. p. 216, pi. 9, fig. 5. 



Cardinal area large, transversely striated, with an indistinct 

 mesial fold ; surface rather smooth, and covered with radiating 

 striae. 



Found in the Mountain Limestone, BoUand. 



4. Spirifer crenistria — The Creni-striated Spirifer, pi. 

 XLIX. fig. 30. 



Spirifera crenistria. Phillips, II. p. 216, pi. 9, fig- 6. 



Cardinal area rather narrow ; mesial fold nearly obsolete ; 

 surface smooth, with strong, very numerous, close-set, divari- 

 cating stria;, which are crossed by pretty strong lines of growth, 

 giving it a crenulated aspect. 



The Mountain Limestone, BoUand. 



5. Spirifer distans The Distant-beaked Spirifer, pi. 



XLIX. fig. 33, 34. 



Spirifer distans. Sowerby, V. p. 153, pi. 494, fig. 3. Fle- 

 ming, p. 375. 



Gibbose, semicircular; sides with from ten to twelve longitu- 

 dinal furrows; cardinal area broad, triangular, and curved; beaks 

 incurved, distant ; mesial ridge plain, elevated in front, with a 

 slight hollow in its centre ; in the opposite valve a furrow. 

 Length about two-thirds of its width. 



The Carboniferous Limestone, near Dublin. 



6. Spirifer septosa. — The Diked Spirifer, pi. XLIX. 

 fig. 35. 



Spirifera septosa. Phillips, II. p. 216, pi. 9, fig. 7. 



Upper valve more convex than the other, both provided with 

 very wide, deep furrows, which in many instances become bifur- 

 cate, or trifurcate, towards the margins; with two strong, diver- 

 gent, intervening ribs on each side. 



Phillips remarks, " The septa in the lower valve divide it into three 

 parts, as in Gypidium, to which by this insufficient character it would 

 be refen-ed. Many Spiriferae exhibit, less distinctly, the same pheno- 

 menon." 



Found in the Mountain Limestone at Burton Fell, Cumber- 

 land, and Ribblehead. 



7. Spirifer rhomboidea. — The Rhomboidal Spirifer, pi. 

 LI. fig. 2 and 16. 



Spirifera rhomboidea. Phillips, II. p. 217, pi. 9, fig- 8, 9. 



Width more than double its length ; cardinal area very wide ; 

 mesial fold well defined ; surface with smooth, rounded, longi- 

 tudinal, divergent ribs, the intervening sulci rather deep, and 

 quite plain. Fig. 16 is a less elongated variety of this species. 



Mountain Limestone, Bolland. 



This species differs fiom S. fusifonnis, in the elevated ridge being 

 much more produced beyond the base, in which character it also disagrees 

 with S. convohita. 



8. Spirifer fusiformis The Spindle-shaped Spirifer, 



pi. LI. fig. 4, 5. 



Spirifera fusiformis. Phillips, II. p. 217, pi. 9, fig. 10, 11. 



Width greatly exceeding its length ; mesial fold not quite 

 central, and ill defined ; cardinal area rather broad, and some- 

 what hollowed ; surface with rather obtuse, longitudinal, diver- 

 gent ribs, and shallow intervening furrows; the rounded central 

 ridge not much produced at the base. 



Mountain Limestone, Bolland. 



9. Spirifer convoluta — The Rolled Spirifer, pi. LI. 

 fig. 15. 



Spirifera convoluta. Phillips, II. p. 217, pi. 9, fig- 7. 



Very much elongated transversely, its width being about 

 thrice its length ; cardinal area concave, with obsolete, remote 

 stria; ; central projection ill defined, as well as the mesial fold ; 

 surface with obtuse, unequal, longitudinal, divergent ribs. 



10. Spirifer triangularis.^ — The Triangular Spirifer, 

 pi. LI. fig. 7. 



Spirifer triangularis. Sowerby, VI. p. 120, pi. 562, fig. 5, 6. 

 Fleming, p. 374. Anomites triangularis, Martin, Pet. Derb. 

 pi. 56, fig. 2. 



Transversely elongated, triangular, convex ; cardinal area 

 flat, with the extremities pointed ; front elevation acute, and 

 producing an angulated appearance in the valve, as well as a 

 sharpness at the base; mesial fold narrow; surface with smooth, 

 rounded, divergent, longitudinal ribs. 



Carboniferous Limestone, Derbyshire. 



11. Spirifer trigonalis. — The Trigonal Spirifer, pi. L. 

 fig. 1, 2, 3, 4. 



Spirifera trigonalis. Sowerby, III. p. 117, pi. 265, fig. 1, 

 2, 3, 4. Fleming, p. 374. Anomites trigonalis, Martin, Pet. 

 Derb. pi. 36, fig. 1. Anomice striata, Ure, Hist. Ruth, and 

 Kilb. p. 314, pi. 15, fig. 1. 



Gibbose ; cardinal area acute at the extremities ; umbones 

 incurved, and approximate ; front or upper valve semicircular, 

 greatly rounded ; surface with longitudinal, divergent ribs, the 



