( 19 ) 



both on Fracture, PI. 1, fig. 8. pi. 2, fig. 7 : it does not appear, however, that he thought 

 of making a longitudinal section of the Echinus, such as M. Beudant has submitted, pi. 

 1, fig. 8. pi. 2, fig. 8. A Belemnite, in the collection of the Conscil des Mines, which has 

 not entirely passed into the calcareous state, presents in some of its parts the same 

 spongy and radiated tissue which we observe in the spines of the Echinus. This Belem- 

 nitc also olfers the peculiarity of a nipple at the base, with projecting sides, striated 

 transversely, and diverging from the centre to the circumference ; the centre is per- 

 forated by a small shallow round hole : the summit sometimes terminates in folds. 

 PI. 1, fig. 10, 11, 12. Some present a large conical cavity at the base, which has been 

 often considered as the last chamber or dwelling of the animal ; others have none, 

 or at least a very small cavity. Theophrastus's description of the lynx stone is not 

 applicable to the Belemnite : it would seem that we owe the first notice of it to 

 Pliny, but it is not quite clear whether his dactylus idceus [P. 37, c. 10) which he 

 clearly distinguishes from the lynx stone (1. 8, c. 38) was a fossil species of Echinus 

 or Belemnite. In the 15th century they were considered to be meteoric stones, and 

 marvellous medicinal virtues were ascribed to them. Boetius de Boot, in his 

 Treatise on Stones, pronounces them to be petrified darts, and it was not until the 

 end of the 16th century that they were first regarded as natural organised bodies. 

 Erhart, in 1724, appears to have been the first who concluded them to be shells 

 akin to the Nautilus. Deluc insisted that the Belemnite was an organised bone, 

 like that of the Sepia ; and they have been concluded by other authors to be sta- 

 lactites ; petrified wood; the teeth or the back bones of fish; the tusks of the 

 Narwal ; Crocodile's teeth ; tubulites, etc. etc. Cuvier, Rdgne Animal \ t. 2. p. 371. 

 Sage, Jour, de Phys. ventose, a«- Beudant, Observations sur les Belemnites. 

 Ann. du Mas. t- 16. p. 77. Faure Biguet. Considerations sur les Belemnites, etc. Lyon, 

 1819. 



Ortlioccr allies. 



Mr. Farey " finds them referable to twenty different places in the British series 

 of strata; extending from fist) the London clay above the chalk, to (20th) the lime- 

 stone resting on slate." According to Spallanzani, the islands of the coasts of Dat- 

 maiia are masses of orthoceratites. M. Sage thinks, from the sections he has made, 

 pi. 1, fig. 24, that the Orthoceratites are alveoli of different species of Belemnites, and' 

 contained within the funnel, pi. 1, fig. 29, which, however, according to M. Beu- 

 dant, does not always exist. This opinion has not been generally adopted. Deluc, in 

 particular, combated it (Journ. de Phys. vent. an. 12.), asserting that the alveoli 

 of* the Belemnites have no siphon. M. Sage considers the organization of the 

 siphon to be evident in pi. l,fig. 27, and in the centre of fig. 25, which is confirmed 



siphon, of a species found most frequently in the marble of Oeland, on the coast of 

 Sweden, four feet long, and only two inches in diameter at the base ; fig. 34, or 

 the same part of another species, whose diameter is three inches, whence he infers 

 its length to be more than five feet ; fig. 11, p. 2, is that of a species from Gothland 

 with a large siphon at the circumference, and remarkable for the projecting rays' 

 sometimes filled with crystals of fluor, the proportion between the length and the' 

 diameter appeared to be 10 : 1. Dhserlatio Physica de Polythalmiis. Gedani, 1732 

 Some are smooth, others have circular sides ; both kinds are found in the greyish 

 marble of Norway ; they are of a whitish calcareous spar, with a case or envelope 

 of a reddish brown ; the chambers are separated by hemispherical yellowish lines. 



Hippurites. 



Some consider what we call the operculum to be the last septum, in which case 

 the shell may be interior, unless it is hereafter discovered to be a bivalve : fig 26 

 pi. 1, shows the gutter or canal, c. which replaces the siphon ; fig. 28 is the under 

 part of a convex operculum, with two prolongations having the appearance of a 



