42 



MOLLUSCA. 



Belemnites. 



tapering towards the apex, and gradually towards the other 

 extremity ; a receptacle for the alveolus is situate towards the 

 base in a conical form, with a longitudinal sulcus upwards of 

 an inch in length. 



Found in the Lower Oolite, Stonnsfield, Oxfordshire ; in 

 the Speeton Clay at Speeton ; and also in the Blue Marie of 

 Bedfordshire and Kent. 



8. B. LisTERi. — Lister's Belemnite, pi. XXIX. fig. 9- 



Belemnites Listeri. Mantell, Geo. of Sussex, p. 88, pi. 19, 

 fig. 17, 18, and 23. B. minima. Lister, Anim. Ang. p. 228, 

 fig. 32. Fleming, Brit. An. p. 240. Phillips, Geo. of York. 

 L p. 120, pi. ], fig. 18. 



Subfusiform, cylindrical, with a single, slight, longitudinal 

 sulcus, and terminating in an acute apex ; siphnncle central, 

 extending through the alveolus to the apex of the spathose 

 part. 



Dr Mantell says, " The form of this beautiful little Belem- 

 nite varies considerably, — some of the specimens are fusiform, 

 others gently taper towards the apex; some are perfectly 

 cylindrical, and others contract suddenly. The longest 

 example in my collection, is 0.2 in diameter, and 1.3 inch in 

 length. These fossils occur in profusion in every locality of 

 the Blue Marie of Sussex, and also in Surrey, Kent, and 

 Cambridgeshire." They also occur in the Red Chalk of 

 Sussex, according to Professor Phillips. 



9- B. voi.OMiNus. — The Scroll Belemnite, pi. XXIX. 

 fig. 10. 



Belemnites mucronatus. Sowerby, Min. Conch. VL p. 207, 

 pi. 600, fig. 7, young shell. 



Shell smooth, fusiform, thickest in the centre, gradually 

 tapering to each extremitj', and terminating in blunt points ; 

 section circvilar. 



Found in the Chalk at Norwich. 



We cannot agree with Sowerby in considering this the 

 young of B. ynucronatus. 



10. B. pisTiLLiFORMis. — The Pestle-shaped Belemnite, 

 pi. XXIX. fig. 22. 



Belemnites pistillifoimis. De Blainville, Mem. sur les 

 Belem. p. 89, pi. 5, fig. 14 to 17. Sowerby, Min. Conch. 

 VL p. 177, pi. 589, fig. 3. 



Shell fusiform, much thickened towards the apex, suddenly 

 and greatly attenuated and elongated towards the base ; sur- 

 face bearing slight impressions of veins. 



Found in the Lias at Shorne Cliff, to the east of Char- 

 mouth. 



11. B. MINIMUS. — The Least Belemnite, pi. XXIX. fig. 

 20, 21. 



Belemnites minimus. Miller, Geo. Trans. 2d Series, II. 

 p. 62, pi. 9, fig. 6. De Blainville, Mem. sur les Belem. p. 

 75, pi. 4, fig. 1, and p. 119, pi. 5, fig. 5. Sowerby, Min. 

 Conch. VI. p. 175, pi. 589, fig. 1. 



Shell fusiform, slightly quadrangular, spreading towards 

 the apex, and cylindrical as it approaches the base, but not 

 expanded ; apex obsoletely papillose ; each side with an 

 obscure double furrow. 



Found in Blue Chalk Marie of Bedfordshire, Folkstone, 

 Maulden, and Cophill. 



12. B. MUCRONATUS. — The Sharp-Pointed Belemnite, pi. 

 XXIX. fig. 15, 16. 



Belemnites mucronatus. Brongniart and Cuvier, Geo. des 

 Env. de Paris, p. .382, pi. 3, fig. 1. De Blainville, Mem. 

 sur les Belem. p. 64, pi. 1, fig. 12. Sowerby, Min. Conch. 



VI. p. 205, pi. 600, fig. 1, 2, 4, 6, 7. B. electrimis, Miller, 

 Geo. Trans. 2d Series, II. p. 61, pi. 8, fig. 18 to 21, and 

 pi. 9, fig. 1 and 3. Belemnite, Faujas, Maestrichf, p. 178, 

 pi. 32, fig. 3. Actinocamax verus. Miller, Geo. Trans. 2d Ser. 

 IL p. 64, pi. 9, fig. 17, 18. 



Shell subcylindrical ; apex terminating abruptly in an 

 obtuse point, with a central mucro ; base expanded, near to 

 which is a slight contraction ; aperture almost circular ; a sul- 

 cus extends along the expanded portion, which communicates 

 with the internal cavity ; a flattened space stretches nearly 

 the whole length of the shell on each side of the back, from 

 whence numerous vein-like channels emanate, and diverging 

 round the sides, meet upon the front of the shell, or enter the 

 sulcus. 



Fig. 16 represents a section of the shell. 



Found in the Upper Chalk of Norwich, and is to be met 

 with in the same stratum of almost every country. 



13. B. ELONGATUS — The Elongated Belemnite, pi. XXIX. 

 fig. 11. 



Beleiiuiites eloTigatus. Miller, Geo. Trans. 2d Series, II 

 p. 60, pi. 7, fig. 6, 7, 8. De Blainville, Mem. sur les Belem- 

 nites, p. 75. Sowerby, Min. Conch. VI. p. 178, pi. 590, 

 fig. 1. A Belemnite, Plott, Phil. Trans. LIV. p. 38, with 

 a figure. 



Shell elongated, slender, and cylindrical in the centre, 

 gradually tapering to an obtuse apex, which is round and 

 plain ; gradually expanding in the other direction to a broad 

 base, and encompassed by numerous obtuse annulations ; 

 chambered portion equal to two-thirds the length of the 

 shell ; diameter of the base equal to about a fourth of its 

 length. 



Found in the Lias Clay at Lyme Regis, Dorsetshire ; 

 Daventry, Northamptonshire ; Charmouth, and vicinity of 

 Bath. 



14. B. ABBREViATUs. — The Shortened Belemnite, pi. 

 XXIX. fig. 18, 19. 



Belemnites ahhreviatus. Miller, Geo. Trans. 2d Series, 

 p. 59, pi. 7, fig. 9 and 10. De Blainville, Mem. sur les 

 Belem. p. 91. Sowerby, Min. Conch. VL p. 179, pi. 590, 

 fig. 2, 3, and 9. 



Shell short, subcylindrical ; fore part abruptly tapering to 

 a slightly recurved eccentric apex, being considerably off the 

 centre ; base expanded ; sides somewhat flattened ; cavity 

 equal to half the length of the shell. 



The considerable thickness in proportion to the length, the 

 contraction and curvature of the point, are distinguishing 

 characteristics of this species. 



Found in the Lias and Inferior Oolite at Weymouth. 



SECTION II. SHELLS STRAIGHT AND CONICAL. 



15. B. AcuTus. — The Acute Belemnite, pi. XXIX. fig. 2. 



Belemnites acutus. Miller, Geo. Trans. 2d Series, II. 

 p. 60, pi. VIIL fig. 9. Sowerby, Min. Conch. VI. p. 180, 

 fig. 7, 8, and 10. 



Shell conical, round, smooth, sides very slightly com- 

 pressed, and destitute of a furrow, terminating in an acute 

 apex ; base broad ; cavity deep and central. 



Found at Shorne Cliff, Charmouth ; and at Weston, near 

 Bath. 



J 



