CREPUSCULAR ANIMALS. 243 



hues, the dull red disc of the setting suu sinks slowly 

 down beneath the horizon, the Noddy and the Frigate 

 Pelican, those " feathered fishers ", seek a resting-place 

 for the night the " Tropic bird wheels rockward to his 

 nest"; the Petrels are no longer seen, the ghost-like 

 Albatross comes sweeping by, the Dolphins cease to 

 bound, and the Acalephce, and other fragile beings of the 

 deep, return to unknown solitudes. But the lovely 

 lanthina, and the fairy-like PJiysalia, do not gather in 

 their floats, but, in company with the giddy Hyalaea, 

 now sport upon the surface ; the Creseis and Cleodora, 

 those living hairs of glass, that glitter in the moon-beam, 

 are more numerous than in the day, and the Argonauta, 

 Carinaria, and Atlanta, take their pleasure on the surface 

 of the sea. 



The Pteropods are little active and energetic Mollusks, 

 common in almost every sea. They are the very butter- 

 flies of the deep, and, from their extreme vivacity, would 

 appear to be possessed of acute sensibilities. Insatiate 

 and greedy, they are ever on the move, spinning, diving, 

 and whirling in every direction. The Hyalcea tridentata 

 reminds one forcibly of the erratic diving and plunging 

 evolutions of the Dyticus, and Hydrophilm of the ponds 

 of Europe. The Pneumodermon, when touched by a 

 foreign body, feigns death, rolling itself up in a ball, like 

 an Armadillo, or Glomeris. The Cleodora Balantium, 

 one of the handsomest of the tribe, is much steadier in 

 its mode of progression, than Ilyalcea, Creseis, or even 

 Cuvieria, owing, probably, to the comparative weakness 

 and small size of the alar membranous expansions. This 

 species, as well as the Cleodora cuspidata, when alive in 



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