404 INVERTEBRATES. 



testaceous, having feet arranged in a circular manner around the 

 heads ; the Pteropods, or wing-footed mollusks ; and the Gastero- 

 poda, or belly-footed. The Acephalous mollusks comprise the 

 Conchiferous, or shell-bearing, and the Tunicated, which are co- 

 vered with a leathery or membranous tunic. 



The Common Cuttle-fish is an example of a naked ce- 

 phalopodous moUusk. This repulsive-looking creature is common 

 on most shores, and is, in spite of its unpleasant appearance, often 

 used for food. Its eight long and flexible arms are covered with 

 suckers of various sizes, enabling their owner not only to fix itself 

 firmly to the rocks on which it dwells, but to seize and retain with 

 the greatest tenacity any unfortunate fish or shell that may happen 

 to come within its reach. Its powerful parrot-like beak enables it 

 not only to devour fishes, but even to crush the shells and Crustacea 

 that are entangled in its deadly embraces. In England the Cuttle 

 does not grow to any great size, but in the Indian Seas it is abso- 

 lutely dangerous, and the crews of boats are forced to be armed 

 with a hatchet, to cut ofi' the arms of the cuttle-fish. 



There are few who have not heard of the color called " sepia." 

 This is, or ought to be, prepared from a black pigment, secreted 

 by the Cuttle-fish, and used in order to escape its foes, by blacken- 

 ing the water with the ink, and hurrying oflf under shelter of the 

 dense cloud of its own creating. Dr. Buckland actually drew a 

 portrait of a fossil Cuttle-fish with some of its own ink that still 

 remained in its body. 



The substance sold in the shops as cuttle-fish bone is a 

 chalky substance secreted from the mouth of the fish, and com- 

 posed of an infinite number of plates, joined by myriads of little 

 pillars. 



The entire body is soft, and encased in a coarse, leather-like 

 skin, unprotected by any shell. 



The Argonaut, or Nautilus, is an example of the Testa- 

 ceous Mollusks. This curious creature, about which so many 

 marvellous and poetical tales have been told, is very abundant in 

 the Mediterranean. 



It has been clearly proved that the Nautilus does not rrg« 



