TABLE OF CONTENTS 
Historical Introduction, 
I. External Conformation and Teguments— 
1. Head, .... 
2. Arms, . 
3. Funnel, Muscles, and Cartilages, 
4. Mantle— 
a. Pallial Envelope, 
b. Terminal Disk, 
a. Fins, 
/3. Aboral Fossa, . 
c. Shell, . 
d. Pallial Cavity, 
II. Nervous System, 
III. Digestive System, 
IV. Circulatory System, . 
V. Excretory System, . 
VI. Reproductive System, 
PAGK 
1 
4 
4 
5 
6 
8 
10 
10 
12 
14 
15 
19 
22 
25 
26 
VII. Classification, 
28 
VIII, Ethology or Bionomics, 
29 
IX. Phylogeny, 
30 
