f Copan.

The shell in the codices is found in most cases to represent zero in the
Maya numerical calculations. Just as a bar has the meaning five, and a
dot one, so the shell often has the signification of zero. This is seen
especially in the numeration by position in the codices (Pl. 1, figs. 7,
8, 10-14).

OTHER MOLLUSCA. In addition to the species just described at least two
or three others occur in the Nuttall Codex, but so conventionalized that
it is out of the question to hazard a guess at their identity. One (Pl.
1, figs. 16, 17) is a bivalve with long pointed shell, another (Pl. 1,
figs. 18-20) is rounder with conventionalized scroll-like markings.
Figs. 21, 22 (Pl. 1) may be a side view of the closed bivalve shown in
figs. 16, 17, or possibly a species of cowry. In like manner, fig. 13 is
probably a side view of the mollusc shown in fig. 14, for it is seen
that in each case the figure showing the two opened valves has a
bipartite extended foot, whereas that of the single valve is simple.
This doubling of the single median foot of the bivalve may be an
artistic necessity for the sake of balance, or perhaps represents both
foot and siphon at the same end. Figs. 23, 24 (Pl. 1) seem to represent
molluscs still further reduced and conventionalized. These molluscs from
the Nuttall Codex (Pl. 1, figs. 15-24) are almost all found represented
in the blue water, whereas those which stand for zero in the Maya
codices have no immediate association with either water or rain.

INSECTA

THE HONEY BEE (_Melipona_). A portion of the Tro-Cortesianus appears to
treat of apiculture, as previously noted, or, at all events, contains
numerous figures of bees, some of which are shown in Pl. 2. As stated by
Stempell (1908, p. 735) this is doubtless a species of _Melipona_,
probably _M. fulvipes_ or _domestica_. It is well known that this bee
was kept by the ancient Mexicans, and what appear to be improvised hives
are shown in Pl. 2, figs. 7, 10, where the combs are noted depending
from the ceiling or walls. These combs are seen to be composed of cells
roughly four-sided for the most part, though in fig. 11 several
hexagonal cells are present in the mass of comb held by the black god,
M. Darwin, in his _Origin of Species_, has called attention to the form
of the comb built by this bee, and considers its irregular cells of from
three to six sides intermediate in their degree of perfection between
those of the bumble bee (_Bombus_)