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BRITISH BELEMNITES. 



De Blainville's great work follows that of Miller, and his classification is in all 

 respects more advanced and comprehensive. It contains eight sections, of which the first 

 is founded on a mistake of Miller, and the last is merely a small appendix of forms which 

 are now distributed in the other sections. 



A. No alveolar cavity. (Actinocamax of Miller.) 



B. Alveolar cavity very small, fissured on the margin, and without septa. (Example 



— Belemnites quadratus. Chalk.) 



C. Alveolar cavity large, fissured on the margin, and without septa. (Example — 



Belemnites mucronatus. Chalk.) 



D. Alveolar cavity large, chambered, siphunculated, with a ventral canal more or less 



evident from the base to the summit of the guard. (Example — B. sulcatum, 

 Miller. Oolite.) 



E. Alveolar cavity large, chambered, siphunculated ; without fissure or canal at the base, 



but with two lateral furrows at the summit of the guard. (Example — B. apici- 

 curvatus, Blainv. Lias.) 



F. Alveolar cavity large, chambered, siphunculated; no fissure or canal at the 



base or furrows at the summit of the guard. (Example — B. abbreviates, 

 Miller. Oolite.) 



G. Alveolar cavity very large in proportion, chambered, siphunculated ; no fissure, 



canal, or grooves. (Example — B. obtusus, copied from Knorr, so as to give 

 quite a wrong notion, but it was previously and better figured by Klein (ix, 2). 

 This section is founded in a mistake.) 



H. Species incompletely known — a mere appendix. 



We have therefore effectively, in Blainville's classification, only five sections of 

 Belemnitidae, two of which (B and C) may be referred to Belemnitella, leaving three (D, 

 E, F) for the restricted genus of Belemnites. 



Blainville adds to his memoir descriptions of Beloptera, Pseudobelus, Rhyncholites, 

 and Conchorhynchus. 



In Bronn's ' Lethaea Geognostica,' 1837, we find the Belemnites ranked in three 

 divisions : 



A. Integra. — Sheath without fissure at the basis, with 7 — furrows at the point. 



Confined to Lias and Inferior Oolite. Subdivisions according to the number of 

 the furrows near the point. 



B. Canaliculatae. — A distinct canal, beginning from the anterior end, or near it, to or 



towards the point on the ventral aspect. (Sometimes another canal opposite 

 this.) On the right and left sides often a fine single or double line from the 



