CLASS OF CEPHALOPODS. 19 



LESSON II. 



Class of Cephalopoda. — General Form — Respiration — Cir- 

 culation — Organs of Digestion — Cephalic Cartilage — 

 Organs of Locomotion --Organs of the Senses — Nervous 

 System — Habits — Division into two Families. 



Family of Cephalopoda Dibranchiata. — Octopus vulgaris, 

 or Poulpe — Argonaut — Calmaries — Cuttle-fishes. 



Family of Cephalopoda Tetrabranchiata. — Nautilus — 

 Ammonites — Belemnites — Foraminafera. 



CIiASS OF CSFKAIiOFODS. 



1. This class is composed of mollusks which are of fantastical 

 shape, for their head is placed between the trunk and feet, or 

 tcntacula, which serve them for locomotion, and when they walk, 

 the body is uppermost, and the head down, dragging on the 

 ground. Their feet are attached, around the mouth, to the head, 

 which circumstance has obtained for them the name of Cephalo- 

 pods (from the Greek, kephale, head, and pous^ foot — pro- 

 nounced hefa-lo-pod). 



Fig. 7. OCTOPUS* VULGARIS, OR COMMON FOULFE. 



2. The trunk of these animals is covered by the mantle, 

 which is in the form of a sack, sometimes almost spherical, 

 and sometimes more or less elongated ; it encloses all the 



* From the Greek, okto^ eight, and pous^ foot, — eight feet. 



1. What kind of animals compose the class of Cephalopods ? Why are 

 they called Cephalopods ? 



2, What are the general form and characters of the Cephalopods ? 



