OF NAUTILUS POMPILIUS. 29 



b, vulva ; c, caruncle at the root of the first branchia ; d, two pair of similar 

 papillae at the bottom of the branchial cavity. 1 , 2, 3, three pair of slits 

 (at the left side of the figure the first is to be seen ; the two others are repre- 

 sented on the right side of the figure). 



Fig. 10. Head of a male Nautilus seen from above ; the hood has been divided by a 

 longitudinal section ; g g are the internal labial processes ; below them, 

 at the right side, is placed and partly visible at i, the external labial 

 processus. The place of it occupies at the left side a large conoid body, a ; 

 m m is the fringed lip inclosing the mandibles. 



Fig. 11. The conoid body of the foregoing figure, separately seen from the inner sur- 

 face, together with the incumbent internal labial processus of the left side. 



Fig. 12. Lateral view of the internal labial processus of the right side, with the man- 

 dibles and the surrounding lip. 



Fig. 13. Penis. A, entire; B, a longitudinal section of it. 



Fig. 14. A portion of the circumvoluted spermatophore or tube contained in the 

 bladder at the basis of the penis. 



PLATE VIIL 



Fig. 5. Side view of the head, the mantle/ being reflected : a, hood ; b, eye ; c c, 



digitations ; d d, funnel. 

 Fig. 6. The same, after removing the digitations ; c, transverse sections of their 



tentacles ; k, external labial processes ; /, internal ditto ; m, membrane 



covering the mandibles. 

 Fig. 7. The same, after removing the external labial processes, cut off at h k. 

 Fig. 8. Caruncle at the peduncle of the eye ; organ of smell, a. 

 Fig. 9. View of the inferior surface of the muscular mass of the mouth, with the 



two cushion-like incised bodies, representing here the folds between the in- 



tei'nal labial processes. 



Leyden, S Dec. 1849. 



VOL. IV. — PART I. 



