204 THE ORIGIN OF VERTEBRATES 
interrupted by two large, remarkable glandular structures. The 
structure of these glands is better shown by means of sagittal sec- 
tions. They are composed of very long, wedge-shaped cells, each of 
which possesses a large, round nucleus at the basal end of the cell 
(Fig. 87), These cells are arranged in bundles of about eight to ten, 
which are separated from each other by connective tissue, the apex 
of each conical bundle being directed into the cavity of the uterus ; 
where this brush-like termination of the cells reaches the surface, the 
chitinous layer is absent, so that this layer is, on surface view, seen 
Fic. 87.—LoneitupinaL Sxc- Fie. 88.—SacitTaL SECTION THROUGH 
TION THROUGH THREE OF THE UTERINE GLAND OF SCORPION, 
THE CONES OF THE UTERINE SHOWING THE INTERNAL CHITINOUS 
GLANDS OF THE SCORPION. SurFace (b) AND THE GLANDULAR 
Conzs (a) CUT THROUGH AT VARIOUS 
DISTANCES FROM THE INTERNAL SUR- 
FACE. 
(Fig. 88 (@)) to be pitted with round holes over that part of the 
internal surface of the uterus where these glands are situated. Each 
of these holes represents the termination of one of these cone-shaped 
wedges of cells. If the section is cut across at right angles to the 
axis of these cones, then its appearance is represented in Fig. 88 («), 
and shows well the arrangement of the blocks of cells, separated from 
each other by connective tissue. When the section passes through 
the basal part of the cones, and only in that case, then the nuclei 
of the cells appear, often in considerable numbers in one section, as 
