BELEMNITES OF THE LIAS. 



53 



Belemxites Bucklandi, n. s. PI. VIII, fig. 18. 



Reference. Belemnites ovalis, Buckland, 'Bridgew. Treatise/ vol. ii, p. 69, pi. xliv', 

 figs. 7, 8, 1836; and 'Bridgew. Treatise/ vol. ii, p. 71, pi. Ixi, figs. 7, 8, 1858. 



GuAED. Slender, smooth, subhastate bv reason of a gentle swelling toward the end, 

 which is convexo-conical and somewhat obtuse, the sides meeting: at an angle of about 

 45°, wdth scarcely a trace of striae or grooves. 



Transverse sections are nearly circular, and show the axial line nearer to the ventral 

 side, which in some specimens is slightly but distinctly flattened. 



Greatest length observed 5'15 inches, of which the axis of the guard occupies 

 2-00 ; the chambered part of the phragmocone appears to occupy the remaining portion 

 of the length (3-15 inches). The greatest diameter below the apex of the alveolar 

 canty 50 inch. 



Proportions. The ventro-dorsal diameter at the alveolar apex being 100, the trans- 

 verse diameter is 96, the ventral radius about 43, the dorsal radius about 57 ; axis, 480 

 in young, 300 in old. 



Phragmocone. Insufficiently known from Dr. Buckland's figure, which represents 

 it with nearly straight sides meeting at an angle of .28°, and septal intervals about ^tli 

 of their diameter — an ordinary proportion. 



Localities. Golden Cap, Lyme Regis, from the Belemnite-bed {Miss Anning, Phillips). 

 The first specimen figured by Dr. Buckland was in the collection of Miss Philpotts. 

 In Upper Lias (sandy part), Blue Wick {P/iillij}s). It has not occurred to me in the 

 Midland Lias, nor do I find it in the large series of Belemnites from the vicinity of 

 Banbury belonging to J\Ir. Stuttard. 



This species has no slight analogy to Belemnites ventro-planus of A'oltz (' Obs. sur les 

 Belem./ pi. i, fig. 10), and to B. umhilicatus of Blainville (' Mem. sur les Belem./ pi. xi, 

 fig. 11). Possibly they are all one species; for the umbilication of the end and the 

 ventral flattening toward the end are not constant characters, and are not absent from 

 some English specimens of B. Bucklandi which I have examined. 



Observations. The opinion of Dr. Buckland, that the extinct Belemnites and the 

 living Sepiadse agreed in possessing an ink-bag, was corroborated by the discovery of 

 the specimen figured in his ' Bridgewater Treatise,' and copied fig. 18, PI. VIII 

 of this Essay. The collection of Miss Philpotts contained this, at that time, " unique 

 specimen," which presents, in a somewhat indistinct roundish mass, what remains of 

 the ink-bag in the anterior part of the phragmocone. " A fracture at b' shows the 

 chambered areolae of the alveolus. At e the thin; conical, anterior, horny sheath originates 

 in the edge of the calcareous sheath, and extends to e". The surface of this anterior 

 sheath exhibits wavy transverse lines of growth ; it is much decomposed, slightly nacreous, 



8 



