230 NAKED MOLLUSKS. 



SECTION II. 



FOSSJL REMAINS OF NAKED MOLLUSKS, PENS, AND INK-BAGS OF 

 LOLIGO. 



It is well known that the common Cuttle Fish, and other 

 living species of Cephalopods,* which have no external 

 shell, are protected from their enemies by a peculiar internal 

 provision, consisting of a bladder-shaped sac, containing a 

 black and viscid ink, the ejection of which defends them, by 

 rendering opaque the water in which they thus become con- 

 cealed. The most familiar examples of this contrivance are 

 found in the Sepia vulgaris, and Loligo of our own seas. 

 (See PL 28, Fig. 1.) 



It was hardly to be expected that we should find, amid 

 the petrified remains of animals of the ancient world, (re- 

 mains which have been buried for countless centuries in the 

 deep foundations of the earth,) traces of so delicate a fluid 

 as the ink which was contained within the bodies of extinct 

 species of Cephalopods, that perished at periods so incalcu- 

 lably remote ; yet the preservation of this substance is esta- 



Argonaiit, Nautilus, lanthina, Lithodomus, Haliotis, and great radiated crys- 

 talline Teredo from the East Indies, exceeded Carara marble in density. 

 This marble and the Haliotis are of equal specific gravities." — De la Beche's 

 Geological Researches, 1834, p. 76. 



* The figure of the common Calmar, or Squid (Loligo Vulgaris Lam. 

 — Sepia loligo of Linnjeus,) see PI. 28, Fig. 1, illustrates the origin of the 

 term Cephalopod, a term applied to a large family of molluscous animals, 

 from the fiict of their feet being placed around tlieir heads. The feet are 

 lined internally with ranges of horny cups, or suckers, by which the animal 

 seizes on its prey, and adheres to extraneous bodies. Tiie mouth, in form 

 and substance resembles a Parrot's beak, and is surrounded by the feet. By 

 means of these feet jmd suckers the Sepia octopus, or common Pouipe (the 

 Polypus of the ancients,) crawls with its head downwards, along the bottom 

 of the sea. 



