148 



GRIFFIN. 



[Voi,. I. 



rial which exists between the ends of the muscles and the 

 shell also extend along the aponeurotic bands. The posterior 

 ventral band is narrower and more difficult to recognize than 

 the others. Each band and muscle leaves a slight, though 

 often distinct, mark upon the inner surface of the shell. 



14 



11 



10 



FIG. i. Nautilus pompilius, female, i. Dorsal flap of mantle. 2. Hood. 3. Eye. 4. Second 

 tentacle, showing papillated surface. 5. Cirrus of tentacle. 6. Tentacle forming sheath for cirrus. 

 7. Funnel. 8. Crus of funnel (M. collaris). 9. Reverted edge of mantle. 10. Occupied chamber 

 of the shell, n. Nidamental gland. 12. End of shell-muscle. 13. Anterior ventral aponeurotic 

 band. 14. Posterior ventral aponeurotic band. 15. Siphuncle. 



These attachments of the mantle to the shell can do little 

 toward holding the Nautilus in its shell ; but they must be of 

 the greatest importance by preventing water from passing 

 between the mantle and shell to the siphon, thus penetrating 

 the chambers and destroying the hydrostatic function of the 

 shell. 



