122 EMISSION OF LIGHT 
has been remarked to emit phosphoric light at cer- 
vain seasons of the year.* 
Among the Rhizopodes, the species named by 
Khrenberg Mammaria scintillans, now better 
known.as Noctiluca miliaris, which is never larger 
than the head of a small pin according to Hum- 
boldt (I never saw one half so large), “ offers to 
the microscopical investigator of Nature, the mag- 
nificent spectacle of a starry firmament reflected 
in the sea.’ Humboldt tells us, in one of his 
works, that his body has remained luminous for 
an hour together, covered as 1t was by Noctiluca, 
after bathing in the waters of the Pacific. 
Noctiluca miliaris is very common in the Eng- 
“lish Channel; and I have found this species in such 
prodigious numbers in the damp sand at Ostend, 
that on raising a handful of it, 1t appeared lke so 
much molten lava. 
In the year 1854, the number of marine animals 
known to be endowed with phosphorescent pro- 
perties during life, amounted to upwards of a 
hundred distinct species, all invertebrata. 
MM. Edoux and Soulezet, two French natu- 
* It would certainly be interesting to introduce some of these 
luminous animals into the marine aquariums which are much 
in vogue at present. For my own part, I have often been de- 
lighted with the phosphorescent spectacle some of them present in 
a small flask. The species figured in the text are perhaps among 
the more worthy of notice in this respect, viz. fig. 19, Thawmantius 
pilosella ; fig. 21, Cydippe pileus ; fig. 22, Beroé Forskalli, ete. 
