CHELETROPIS, AND OTHER PELAGIC GASTEROPODA. 
297 
Explanation of Figures in Plate XVI. 
Fig. 16. Front view of Macgillivrayia pelagica, with its ciliated arms {a) extended 
and encircling the mouth and tentaciila {b). c. Open canal of respiratory 
siphon, d. The foot. 
Fig. 17 . Lateral view of ditto, a. Ciliated appendages. 6. Portion of left tentaculmn. 
c. Siphon, d. The foot. e. Operculum. 
Fig. 18. Enlarged figure of a minute pelagic Gasteropod, presenting six ciliated arms 
(a), similar to those of Macgillivrayia, b. Tentacula, bearing each an 
ocellus on the outer side near the base. c. Rudimentary creeping disc. 
d. Operculigerous lobe, e. Operculum. 
Fig. 19. Two transverse rows of the lingual teeth of this little animal. 
Fig. 20. Front view of shell of ditto. 
Fig. 21. Back view of same. 
Fig. 22. The operculum, with its clawed process (internal surface). 
Fig. 23. Front view of the closed shell of another minute species. 
Fig. 24. Back view of ditto ; the retracted arms, the ocelli, and the anterior lobes of 
the foot, appearing through the transparent wall of the shell*. 
* Figures of the above genera were given in the illustrations of the former paper. 
