796 NATURAL HISTORY MISCELLANY. 
at an equal angle on each side of the axis of the instrument, are 
crossed and at the same time rendered achromatic by wedge-shaped 
prisms of flint glass placed base to base, and proceed to the two 
eye-pieces through tubes symmetrically situated in reference to the 
axis of the instrument, as in Mr. Wenham’s early proposals for re- 
fracting binoculars. Adjustment for distance of eyes is made, as 
in Wenham’s present arrangement, by a draw-tube movement. In 
stereoscopic effect, as well as in illumination (only one of the two 
polarized rays being utilized), the new arrangement is no doubt 
inferior to Tolles’ binocular eye-piece, but it possesses the great 
advantage of enabling the eyes to look at the object, through the 
convergent tubes, at the natural angle of near vision. It may be 
made in the form of an eye-piece applicable to any large stand; 
or, more satisfactorily, as a supplementary compound body capa- 
ble of being easily fitted to any stand of suitable size, and of be- 
ing used interchangeably with the regular body belonging to the 
stand.— R. H. Warp. 
Nature or Cru1ary Movement.—Professor Heckel has made 
some highly important observations on the nature of ciliary move- 
ment, as we find in the ‘ Quarterly Journal of Microscopical Sci- 
ence.” Recent investigations by others had shown that physiolog- 
ically the ciliary is much more nearly related to the amoeboid 
movement than to the muscular. Heckel shows that the ciliary 
is merely a modification of the amwboid movement of protoplasm. 
“ Ciliated cells are of two kinds. In the one kind, Epithelium 
Jlagellatum, each cell is provided with a single long flagellum or 
lash. Sponges possess only this kind; in the other, Epithelium 
ciliatum, numerous hair-like appendages take the place of the 
flagellum. This is the kind found in most of the higher animals. 
The old notion, that in ciliated cells the cilia are attached to the 
outside of the cell membrane, must now be considered as entirely 
set aside. Many, probably most, ciliated cells are destitute of a 
membrane, and the appendages, whether flagella or cilia, are di- 
rect processes of the protoplasm of the cell.” Prof. Heckel’s 
observations on lower organisms during the last year have led him 
to the conclusion that ciliated cells arise directly by the transmu- 
tation of ameeboid cells. 
COMBINATION OF THE SPECTROSCOPE AND Porariscorr. — Mr. 
Francis Deas has introduced to the Royal Society of Edinburgh 
