JURASSIC ANIMALS. 



433 



escape its enemy. These ink-bags are often well preserved (Fig. 663), 

 and the fossil ink has been found to make good pigment (sepia), and 

 drawings of these extinct animals have actually been 

 made with the fossil ink of their own ink-bags 

 (Buckland). Belemnites were some of them of 

 great size, and evidently formidable animals. The 

 bone of the Belemnites giganteus has been found 

 two feet long and three to four inches in diameter 

 at the larger or hollow end. A very perfect speci- 

 men of an allied genus, from the Oolite of England, 

 is shown in Fig. 668. 



Fig. 664. 



Fig. 663. 



Fig. 667. 



Fig. 668. 



Figs. 663-668.-663. Fossil Ink-Bags of Belemnites. 664. Belemnites Owenii. 665! Belemnites has- 

 tatus. 666. Belemnites unicanaliculatus. 667. Belemnites clavatas. 668. Acanthoteuthis anti- 

 quum (after Mantell). 



The following diagram shows the order of succession of families of 

 the class Cephalopoda : 



