12 LIVING LIGHTS. 



forms may be seen passing in review. Peering down into 

 the depths from our boat, we may see a pretty, shapely 

 jelly-fish, called Zygodactyla, a golden ignis fatuus of the ocean 

 waters; the Melicertus, another of the same family, sur- 

 rounded by a golden radiance ; and a stately RMzostoma, 

 which Giglioli observed in fresh or brackish water in Batavia, 

 emitting a fixed, bluish light; while Zina, Coryne, Eucope 

 and Clytia, and a host of other exceedingly pretty sea-jellies, 

 add to the glories of the scene. 



The delicate Thaumantius (Plate III., Fig. 3) and Oceanea 

 are resplendent light-givers. The latter, according to Ehren- 

 berg, being "surrounded by a shining crown," while Pelagia 

 illumines the deep sea by its mystic rays. 



Although we have established a rule to refer the most 

 of the technical names, with the more scientific matter, to 

 the Appendix notes, we are yet inclined to retain in the 

 text, occasionally, some names which are especially attrac- 

 tive. Thousands of marine animals have no other name 

 but the generic ones given them by discoverers; but in 

 many instances they are pretty, and there is no reason 

 why they should not be used, as they must become the 

 common name of the object, as well as its technical 

 one. 



Other known light-givers are recorded in the Appendix, 5 

 all forms of the greatest delicacy and beauty. 



Of a brilliantly phosphorescent form, 6 Professor Alexander 

 Agassiz says, " When passing through shoals of these 

 medusce, ranging in size from a pin's head to several inches 

 in length, the whole water becomes so wonderfully luminous 

 that an oar dipped in the water up to the handle can be 

 seen plainly on dark nights by the light so produced. The 



