250 



CEPHALOPODA. 



Phragmoceras. 



With about tbree rather compressed vohitions, the inner 

 ones slightly indenting those around them ; surface with 

 numerous transverse arcuated ribs, which are lost over the mar- 

 gin ; aperture somewhat quadrangular, with rounded corners ; 

 siphunole nearly central. Diameter of last volution four and 

 a half inches, length of aperture one inch and three-fourths, 

 width eight lines. 



Fig. 3 represents a portion of the back, and fig. 2 a section. 



The Wenlock Limestone, Mocktree Hays, and Chum Bank, 

 near Ludlow. 



1. Cltmenia linearis. — The Lined Clymenia, pi. III.* 

 figs. 4, 5. 



C. linearis. Sowerby, Geo. Tr. 2nd. Ser. V. pi. 54, fig. 19. 

 Endosiphonites carinatus. Ansted, Camb. Tr. VI. pi. 8, figs. 

 1, 2, 3. 



Discoidal, convolute, the inner volutions ; back with a smooth, 

 narrow, central keel ; section of the volution elliptical, oblong, 

 impressed by the inner volution ; siphuncle small ; surface 

 covered with gently bent transverse strise ; septa obsolete. 



In the Devonian Shales, Petherwin. 



1. NuMiiuLiTEs ELEG.\NS. — The Elegant Nummulites, pi. 

 XXVI. figs. 9, 10, 11. 



N. elegans. Sowerby, VI. p. 76, pi. 538, fig. 2. 



Greatly compressed, smooth, consisting of about six volu- 

 tions; septa numerous, and gently curved from the axis; aper- 

 ture rather prominent. 



This species differs from N. Javigata in being smaller and 

 having fewer volutions, which increase more rapidly, and in the 

 regular curvature of the septa. In the young condition it is 

 veiy smooth and lenticular. 



In the London Clay, Emsworth, Sussex. 



1 . Ctrtoceras NAUTiLoroEtJM. — The Nautilus-shaped Cyr- 

 toceras, pi. III.* figs. 7, 8, 9. 



C. Naiitiloideum. Phillips, Pal. Fos. p. 1 1 6, pi. 40, fig. 200. 



Involute, tapering ; section nearly circular ; septa slightly 

 oblique ; siphuncle situate near the back, almost half way from 

 the centre toward the convex line of the shell. 



Fig. 8, a chamber of C. marginale, seen on the face ; fig. 9, 

 ditto on the edge. 



In the Devonian Shales, Newton Bushel. 



1. AcTiNOCERAS SiMMSii. — Simm's Actinoceras, pi. III.* 

 fig. 6. 



A. Simmsii. Stokes, Geo. Tr. 2nd Ser. V. p. 708, pi. 59, 

 fig. 4. 



Shell large, conical, the upper chamber very deep ; siphuncle 

 large, continuous, and contracted at the attachments ; septa 

 composed of several laminae, and rather thick. Length upwards 

 of two feet. 



In the Carboniferous Limestone, Castle Espie, Ireland. 



1. GoMPHocERAs PYRiFORME. — The Pear-shsped Gompho- 

 ceras, pi. III.* fig. 10. 



Orthoceras pyri/orme. Sowerby, Sil. Syst. p. 020, pi. 8, 

 figs. 19, 20. 



Ovate, pear-shaped, with chambered portion elongated ; septa 

 numerous, and even ; siphunole rather large, situate half way 

 between the centre and margin, and inflated between the 

 septa ; aperture narrow, enlarged at one extremity where the 

 ridge is reflected ; surface smooth. Length of inflated portion 

 four inches, diameter of ditto two and a half inches. 



The Upper Silurian Series, Aymsti-ey, Ledbury, ttc. 



1. Ckioceras BowERBANKii. — Bowerbank's Crioceras, pi. 

 III.* figs. 12, 13. 



C. Boiverbankii. Sowerby, Geo. Tr. 2nd Ser. V. p. 410, 

 pi. 34, fig. 1. 



With four volutions, slightly flattened on the sides, and 

 nearly close ; the inner ones with numerous radiating furrows, 

 which, gradually disappearing upon the outer volution, are 

 succeeded by eight or ten thick, arcuated ribs, extending across 

 the volution, and are largest and most elevated towards the 

 aperture, which is thinly edged and transversely oblong. 

 Diameter seven and a half inches ; breadth of aperture two 

 and a half inches. 



In the Lower Greensand, Isle of Wight. 



1. Phragmoceras tentrioosdm. — The Bellied Phragmo- 

 ceras, pi. III.* fig. 11. 



P. ventricosum. Sowerby, Sil. Sys. p. 621, pi. 10, f. 4, 5, 6. 



Compressed, slightly arcuated, and somewhat hooked near 

 the apex ; aperture nearly closed in the middle ; beak produced ; 

 surface "with many ridges, which cross the edges of the 

 numerous septa. 



The Lower Ludlow Kock, Aymestry, Dudley, &c 



1. VoLUTA Cithaba.— The Hai-p Voluta, pi. XXXVII.* 

 figs. 1, 2. 



