180 BULLETIN OF THE 



An octant of the disk of Cyanca sliowing the early condition of the chymif- 



crous tubes, the sexual filaments, and the bundles of marginal tentacles. 

 Octant of the eph}Ta of C arctica (oral view). 



s. Single sexual filament. 

 Still more developed ephyra of the same (oral view). 



Aboral view of the region of the bell margin in which the sense organ is 

 situated {Cyanea). 

 Fig. 12. Marginal sense organ of Cyanea. 



c. Single curtain hanging down on the left-hand side of the otocyst. 

 Fig. 12*. Hood covering the otocyst on aboral side. 



Fig. 13. Sexual organs and sexual filaments of Cyanca (female). 

 Fig. 14. Peculiar sense organ (?) on the under side of the peduncle of the marginal 

 sense organ of Cyanea. 



PLATE VIIL 



Fig, 1. Mnemiopsis Leidyi, expanded, life size. 



Fig. 2. The same, contracted and seen in a plane at right angles to Fig. 1. 



a. Sense pockets of the tentacle. 



h. Vfbratile plate. 



i. Intestine, with surrounding glands. 



j. Rudimentary tentacle. 



I. Vibratile combs. 

 Fig. 3. Young of Fig. 1 (Mnemiopsis Leidyi) with embryonic tentacles extended. 

 Fig. 4. Side view of the same. 

 Fig. 5. Aboral view of the young of M. Leidyi a little younger than those figured 



in Figs. 3, 4. 

 Fig, 5', Sense area of young Mnemiopsis. 

 Fig. 6. Sense organ, with nerves (d) of adult Mnemiopsis. 

 Fig. 7. Eudimentary tentacle of a young Mnemiopsis. 

 Fig. 8. Rudimentary tentacle of the adult of the same. 



a. Sense pockets. 



b. ChjTniferous tube. 



d. H od covering the rudimentary tentacles. 



Fig. 9. Side view of the tentacle raised from the socket in which it lies. 

 Fig. 10. Place of junction of tubes in the angle made by the oral lappets and the 

 body of the Ctenophore (Mnemiopsis). 



e. Tube from the ambulacral combs. 



/. Row of pigment spots extending to the tentacle, and bearing small 

 thread-like tentacles. 

 Fig. 11. Cells found forming a network on the inner surface of the oral lappets of 



Mnemiopsis. 

 Fig. 14. Daclylometra quinquecirra, A. Ag. 



PLATE IX. 



Fig. 1, Young of Agalmxi elcgans. 

 Fig. 2. Athorybia stage of ^. e/rja7i.s. 



