138 UTILIZATION OF MINUTE LIFE. 



itself instantaneously, as numerous observations 

 show. They walk upon the bottom of the ocean, 

 head downwards, making use of their tentacles 

 as feet. 



The different varieties of Cuttlefish are provided 

 with a very peculiar organ, generally known as 

 ' ' the ink-bag" a purse-like sac filled with a dark- 

 coloured liquid, which is secreted by a special 

 gland. When the animal is irritated or frightened, 

 it empties a quantity of this fluid into the water to 

 conceal itself. 



This coloured liquid was used by the ancients as 

 a kind of ink, and it has been affirmed that it 

 formed the basis of several paints, among others of 

 China or India ink; but the latter often owes its 

 colour to the charcoal of burnt cork, or to common 

 lampblack mixed with glue. 



The drawings with which Cuvier illustrated his 

 studies of the Sepia, Loligo, and other Cephalopoda, 

 were executed with the ink furnished by the animals 

 he was dissecting. 



Miss Mary Anning, of Lyme Regis, formerly 

 discovered that the ink-bags of certain fossil Cepha- 

 lopoda in the Lias beds has been preserved un- 

 altered to the present day, though it must have 

 lain buried in the strata for myriads of centuries ! 

 f( In the lower Jura formations" (the lias of Lyme 

 Kegis), says Humboldt, " the ink-bag of the Sepia 



