Miss Agnes Crane — Recent and Fossil Cephalopoda. 495 



known appearance of tlie group is in the Trias, when the extinct 

 family of Belemnites, which subsequently became such a marked 

 feature in the Jurassic seas, was first represented by a few forms 

 which were the contemporaries of the last surviving members of the 

 once powerful race of Orthocerata. These apparently primitive 

 Belemnites lived in the shallow seas in which were deposited the 

 St. Cassian beds of geologists (situated in the Austrian Alps), so 

 famous for the admixture of Palaeozoic and Secondary types, and 

 as serving to indicate the absolute continuity of the geological 

 series. Of the now numerous family of Octopods, we have no 

 trace in a fossil state, although, as already stated, their horny 

 mandibles are susceptible of preservation. Beaks, of a similar 

 horny texture, occur in rocks of Secondary and Tertiary age ; but 

 their size and shape is suggestive of their belonging either to the 

 fossil cuttles and squids, or to their extinct allies, the Belemnitidoe, 

 whose remains are associated with them in the same strata. The 

 inference that giant naked Cephalopods existed in the Palseozoic seas 

 with calcareous jaws^ is, of course, a purely speculative one. The 

 distribution of the true cuttles (the Sepiadce) is universal in the 

 existing oceans. Eemains of the family are preserved in the Lias 

 Oxford clay, other Oolitic deposits, and in the Tertiaries. The 

 living TetithidcB, the Calamaries, or squids, are also widely dis- 

 tributed. They are found fossil in the Upper Liassic, Oolitic, 

 Cretaceous, and Tertiary formations. 



The history of the organization of the fossils comprising the 

 remaining dibranchiate family, the now wholly extinct Belemnitidce, 

 was long involved in mystery. Specimens of the remarkable genus, 

 Belemnoteiithis, were preserved in a marvellously perfect manner 

 in the Oxford clay, at Chippenham, in Wiltshire, the mantle, 

 fins, eye sockets, beaks, and tentacles being all entombed in juxta- 

 position. The internal, vertically chambered, partly calcareous 

 skeleton, is attached to a hoi'ny pointed guard, resembling the 

 familiar " thunder-bolt " of our childhood. The animal was indeed 

 first described by Professor Owen,^ in 1844:, as that of the true 

 Belemnite ; but it is now considered as being more allied to the 

 Calamaries, especially to the genus Onychoteuthis, now existing in 

 the Indian Ocean, the tentacles in both forms being armed with a 

 double series of formidable horny hooks. Dr. Mantell ^ first showed 

 that this curious fossil possessed some points of internal structure 

 that could not have been associated with, or fitted into, the horny 

 guards forming the apex of the chambered skeleton of the Belemnite, 

 and the affinities of Belemnoteuthis were then recognized as being 

 •with the Calamaries ; but Professor Owen still maintains that it 

 illustrates the close connexion existing between the two groups of 

 organisms. Indeed, the Belemnitidce may be fairly regarded merely 

 as an extinct branch of the Squid family. The presence of an 

 ink-bag and ten arms in the animal to which the appendage known 

 as the Belemnite belonged, was first suspected by Dr. Buckland;' 



1 Phil. Trans., 1844. On the animal of Belemnite. 



2 Phil. Trans., 1848 and 1850. 3 Bridgewater Treatise, 1836. 



