CEPHALOPODA. 7 



duced, truncated and furnished with a deep conical cavity (the alveolus), containing the 

 distal portion of a horny or fibro-calcareous chambered shell (the phragmacone), perforated 

 on the ventral part by a marginal siphuncle, and from the dorso-lateral margins of the 

 anterior extremity of which shell proceed two elongated, slender, testaceous processes ; the 

 whole body being invested with a thin, testaceous, or corneo-calcareous integument (the 

 capsule, or p eriostricum ) . l 



1 On the subject of the Belemnite and allied forms, the reader is referred to the Memoir by Professor 

 Owen, in the 'Phil. Trans.,' 1844, p. 65 ; and the interesting papers in the same work, by G. A. Mantell, 

 Esq., LL.D., 'Phil. Trans.,' 1848, p. 171, and 1850, p. 393; also to the ' Paleontologie Franchise, Terrains 

 Jurassiques,' p. 40, by M. A. D'Orbigny. 



In corroboration of the interesting facts cited by Dr. Mantell, respecting the continuation of the 

 phragmacone of the Belemnite, we quote the following graphic statement of a writer of the last century as 

 bearing on the subject. The remarks are contained in an account descriptive of the sinking of a well at 

 Montbard, in 1774. 



"There were, moveover, great numbers of Belemnites, all conical, the largest being from 7 to 8 inches 

 long. They were pointed like an arrow at one end, and the other terminated irregularly, and was flattened, 

 as if they had been crushed. They were brown, both on the outside and inside, and were formed of a 

 material, arranged internally in transverse or radiating striae, which met at the axis of the Belemnite. This 

 axis was, in all, rather eccentric, and marked from one extremity to the other by a fine white line. When- 

 ever the Belemnite attained a certain size, the base contained a small cone, more or less long, made up of 

 cells, in the form of plates set one within the other (as in Nautili). The white line ended at the summit of 

 the cone. This small cone was invested along its whole length by a yellowish crustaceous pellicle, extremely 

 thin, although composed of several layers ; and the body of the Belemnite (with a radiating structure), 

 which enclosed the whole, became thin in proportion as the diameter of the cone increased. Such, 

 generally, was the character of the Belemnites which were found mingled with the soil thrown out of the 

 shaft, and which character is common to all those of this species. In order to ascertain the position which 

 the Belemnites occupied in the beds, several portions were softened carefully, and it was found that they all 

 laid flat, and parallel with the beds. What most astonished us, and what has not hitherto been noticed, was 

 this, that we then perceived, that to the extremity of the base of all the Belemnites, was attached an 

 appendage of a yellowish colour, composed of a substance like that of the shells, and which was shaped like 

 the widened part of a funnel which had been flattened. Many of these were two inches long, one inch 

 broad at the further end, and about six lines at the point where they were attached to the Belemnite. In 

 examining closely this shelly or crustaceous prolongation (which was so delicate that it could scarcely be 

 touched without breaking), I observed that this part of the Belemnite, which has not hitherto been recog- 

 nised, is nothing more than the continuation of the thin shell or crust which covers the little chambered 

 cone, of which I have already spoken ; so that it may be said, that all Belemnites which are at present to 

 be found in collections of Natural History are imperfect ; and that the portion we are acquainted with is 

 only, as it were, the case or covering of a portion of the shell which at one time enclosed the animal." 



Buffon, 'Epochs de la Nature,' hi, Epoch 5, p. 143. 



' Historie des Mineraux, des argiles et de glaises,' vi, p. 122. 



The above passage is translated from the 'Explication de la Carte Geologique de France,' torn. 2, 

 p. 350. 



