4 BRITISH FOSSILS. 



to the base of the ink-bag there is a series of circular transverse 

 plates and narrow chambers, resembling the chambered alveolus 

 within the' cone of a belemnite ; but, beyond the apex of this alveolus, 

 no spathose body has been found. 



" The author infers that the animal from which these fossil ink-bags 

 are derived, was some unknown cephalopod, nearly allied in its 

 internal structure to the inhabitant of the belemnite ; the circular 

 form of the septa showing that they cannot be referred to the 

 molluscous inhabitant of any nautilus or cornu-ammonis." 



This is, so far as I am aware, the first notice of the existence of a 

 pro-ostracum in a Belemnite. 



Voltz, writing in 1830, had no direct knowledge of the existence of 

 any such structui'e, though he was led by observation of the lines of 

 growth of the conotheca, to conclude that it was prolonged dorsally ; 

 but, in the same year, Count Minister* published descriptions and 

 figures of Belemnites with complete pro-ostraca. 



" In the Belemnites there is an empty prolongation, similar to the 

 last open chamber, of the guard, which is as long as the thick and 

 chambered shell, but infinitely more delicate, as in the Orthoceratites. 

 and hardly of the thickness*of the skin of a bladder." 



The species which exhibited this pen in the best state of preserva- 

 tion was Belemnites scmisulcatus, complete specimens of which, from 

 the Solenhofen slates, are represented in Count Minister's third and 

 fourth figures. 



Dr. Bucklaud returns to the subject in his '' Bridgewater Treatise " 

 (1836), page 374, note. 



" In 1829, I communicated to the Geological Society of London a 

 notice respecting the probable connection of Belemnites with certain 

 fossil ink-bags, surrounded by brilliant nacre, found in the Lias at Lyme 

 Regis. (See Phil. Mag., N.S., 1829, p. 388.) At the same time I 

 caused to be prepared the drawings of fossils engraved in Plate 44", 

 which induced me to consider these ink-bags as derived from Cephalo- 

 pods connected with Belemnites. I then withheld their publication. 

 in the hope of discovering certain demonstration, in some specimens 

 that should present these ink-bags in connection with the sheath or 

 body of a Belemnite, and this demonstration has at length been 

 furnished by a discovery made by Professor Agassiz (October 1834), in 

 the cabinet of Miss Philpotts, at Lyme Regis, of two important speci- 

 mens which appear to be decisive of the question. (See PI. 44', 

 figs. 7-9. 



" Each of these specimens contains an ink-bag within the anterior 

 portion of the sheath of a perfect Belemnite ; and we are henceforth 

 enabled with certainty to refer all species of Belemnites to a family in 

 the class of Cephalopods for which I would, in concurrence with 

 M. Agassiz, propose the name of Belemnosepia."\ Such ink-bags are 



* " Nouvelles Observations sur les Belemnites, in Boue's Memoires Geologiques," 

 translated from " Bemerkungen zur niiheren Kenntniss der Belemniten." 4to. Bai- 

 reuth, 1850, p. 296. 



fBuckland it is obvious, proposes Belemnoscpia as a name for the animal, or ' family ' 

 of animals to which the shell called " Belemnite " belongs, and not as a name for the 

 particular specimens which he examined. Those who have considered these speci- 

 mens not to belong to the family of the Belemnitida: at all, therefore, but to the 

 Teuthidcp or Loligida*, are not justified in using Belemnosepia as a generic title for 

 the intention of the authors of that name is to employ Belemnosepia as the equivalent 

 of Belemnites in its ordinary acceptation; and as naturalists have refused to do so, 

 and continue, as I think, wisely, to nse "Belemnites" for the genus of animals 

 which fabricate the shell called " Belemnite," Belemrwsepia remains as a mere syno- 

 nym, and can be employed in no other sense. 



