326 GASTEROPODES. 



of experiment on the different species of such creatures generated amidst 

 albuminous matter. 



Meantime the production of the Nautiline, whether a larva onot, 

 from the spawn of the Doris, is alike positive and invariable as of the 

 embryo and the chick from the ovum of a fish or of a bird. 



PLATE XLVI. 



FIG. 1. Spawn, resembling a thick drop deposited on a marine vegetable. 

 Parent unknown. 



2. Nautiline produced by the same, enlarged. 



3. Two Nautilines, each within its respective integument, still contained 



in an ovoidal mass of spawn from an unknown parent, enlarged. 



4. The same two Nautilines when free, enlarged. 



5. Nautiline from another ovoidal mass of spawn, parent unknown, 



enlarged. 



6. Two shells of Nautilines belonging to the same ovoidal mas.s, en- 



larged. 



7. Clusters composed of capsules of spawn. Parent unknown. 



8. A capsule from the same clusters, which contained quiescent cor- 



puscula, enlarged. 



9. Another. 



10. Another. 



11. A capsule from the cluster composing fig. 7, containing active cor- 



puscula, enlarged. 



12. Another. 



13. Corpuscula still confined in fig. 12, (each should be circumscribed 



by a faint line), enlarged. 



14. Nautilines from the same, free, active, enlarged. 



15. Nautilines in retreat, enlarged. 



16. Empty shells of Nautilines, enlarged. 



17. Five capsules of spawn, connected by slender ligaments. Parent 



unknown. 



18. The same five capsules, enlarged. 



19. Three active Nautilines from the same, enlarged. 



20. Empty shells. 



All the figures of this Plate, except 1, 7, 1 7, are enlarged. 



