gE a a T 
AMERICAN NATURALIST. 
Vol. V.— OCTOBER, 1871.—No. 10. 
CABO) OD> 
EXPERIMENTS WITH VIBRATING CILLA. 
BY JEFFRIES WYMAN, M.D. 
—_+4-—_—_— 
Tue motions of vibrating cilia, and their action on the water 
around them, are among the most beautiful sights shown by the mi- 
croscope. They are best seen on the respiratory surfaces of both 
land and aquatic animals, and of the last, the gills of the Mytili 
are especially favorable for examination. In such cases, the effects 
are confined to the movement of the secreted mucus, or of the 
surrounding water, and the particles floating in it, while in 
others the cilia cover the outer surface and become the chief or- 
gans of locomotion, as in the Infusoria. In the eggs of Radi- 
ates and Molluscs, as in the remarkable phenomenon of fhe rota- 
tion of the yolk, much larger masses are moved, and among 
Batrachians, the yolk, soon after impregnation and segmentation, 
being large enough to be easily watched with the naked eye, is 
seen to revolve steadily under ciliary influence. Even the re- 
age hatched larve of frogs and toads are carried along bodily 
b same agents distributed over the whole outward surface., 
a the slightest aid from the muscular system. In all of 
these aniio however, although in some the mass moved is con- 
siderable, the motion takes place in a fluid, of nearly the same 
specific gravity as the objects, and so the forae required to give 
the motion is exceedingly small. Indeed everything serves to 
give the impression that cilia are capable of exerting only the 
Entered according to Act of Congress, in the year 1871, by the PEABODY ACADEMY OF 
SCIENCE, in ain Office of the Librarian of Congress, at Washington. 
Al 
TURALIST, VOL. V. 39 (611) 
