of the Island of St. Paul. 357 
visible in November and December ; but the number of 76 indi- 
genous forms of the larger plants and animals appears to be 
very nearly the extreme limit of the palpable life of the island, 
and may be adopted here only as a standard of comparison with 
the microscopic impalpable life. 
THE MICROSCOPIC FORMS OF LIFE. 
Professor Hochstetter sent me first of all some specimens of 
cinders and earths from the base and the elevated surface of the 
voleano. The increasing interest of the investigation induced 
me to make special requests, and called forth from Professor 
Hochstetter further explanations and the transmission of other 
materials. In this way I obtained fifteen different samples. 
Review and Characteristics of the Materials. 
a. From the shore and base of the crater. 
1. Sand from the hot place close to the shore of the crater- 
basin. No. 171.—The spot is covered by the sea at high water. 
At a depth of 4-1 foot, the thermometer rose to 168°, 187°, 
196°, 197°°6, and 201° F. The bare foot could not bear to rest 
on the surface, and was scalded when slightly sunk. The spe- 
cimen is dry, and consists of a moderately fine sharp sand of a 
dark-grey colour, with numerous black, yellowish, and white 
grains, mostly a little coarser than ordinary writing-sand. Acids 
produce no perceptible effervescence. When heated to redness, 
many of the dark particles become paler, and the brown ones 
more yellowish. Ten analyses of the finest parts, suspended 
in distilled water, gave only a slight intermixture of organic 
particles in a greatly predominating mass of sand composed of 
cindery fragments of different colours, many of which were 
doubly refractive. Only two Polygastria and three Phytolitharia 
could be particularly registered; they were all completely iso- 
lated. From the scanty intermixture of the latter, this sand 
evidently has no connexion with the humus of the island; and 
although the two Polygastria establish beyond a doubt a con- 
nexion with the neighbouring sea, all the intermixed calcareous 
particles of sea-sand are wanting. The sand consequently con- 
sists of fine cindery particles, and of a few accidentally intro- 
duced terrestrial and marine organisms of the smallest size. 
Each of the analyses here given relates, as in other cases, 
to about one-third of a cubic line (a portion as large as a 
pin’s head) of the mass, spread thinly with water upon mica, 
dried, and coated with Canada balsam: every particle of this, 
however small, was examined with a power of 300 diameters. 
Ann. & Mag. N. Hist. Ser. 3. Vol. ix. 26 
