ANTHROPOLOGY. MICROSCOPY. 443 
n the contrary, considerations drawn from physical geography, 
and especially the deep sea soundings made by the ‘‘ Challenger,” 
seem to go against the view of intercontinental bridges held by 
some naturalists. We look for a solution of the resemblance of 
the tertiary fauna of Europe and north temperate America, to a 
study of the tertiary lands of Arctic America, Greenland and Spitz- 
bergen, from which the European forms of an American type may 
have emigrated in preglacial times. 
ANTHROPOLOGY. 
Tue Pyemres or CENTRAL Arrica.— Dr. Schweinfurth has stud- 
ied and drawn the Akka or pygmy race of Central Africa, whose 
average height is four feet six inches. The statements of Hero- 
dotus and Aristotle are thus fully confirmed. 
MICROSCOPY. 
AMPHIPLEURA PELLUCIDA IN DoTs.— A y objective was made by 
Tolles to my order, and finished on the 12th of March, 1873. The 
angle of aperture as invoiced by Mr. Stodder is 165°. From my 
measurements I think the objective is correctly named by the 
maker. At the extreme open point it is a good sth dry. The 
screw-collar has twelve divisions: by turning it eight divisions it 
is adjusted for uncovered wet, and four divisions remain to adjust 
for cover for immersion work. It works through covering glass of 
about 245th of an inch, but it is better to use rame be or 
mica, to enable the observer to focus through specim 
pellucida is better than I have before seen. Using ordinary day- 
light, Vibriones, Bacteria, etc., are well defined, especially when a 
Kelner eye-piece is used as a condenser. 
With sunlight and the ammonia-sulphate of copper cell, Su- 
rirella gemma yields longitudinal striæ, and, as the direction of the 
light is changed, rows of ‘“ hemispherical bosses” as described by 
Dr. Woodward. 
With the same illumination specimens of Amphipleura pellucida, 
mounted dry, by Norman, were resolved and counted with perfect 
ase and remarkable plainness, the striz being still distinctly visi- 
ble with No. 3, eye-piece, draw-tube extended six inches, and 
Power upward of 10,000 times. 
