JONES—TRAILS, TRACKS, AND SURFACE-MARKINGS.
137
with water. The eggs themselves are sold in cakes in the market, pounded and cooked, and also in lumps au naturel, forming a substance like the roe of a fish. This is known by the characteristic name of 'ahuauhtl,' that is, 'water-wheat.'"
Fig. 10.—A piece of the dried clay bed of a pond in Kent. a, a, ova of boat-flies (?); b, b′ b″, galleries, with raised roofs, made by water-insects; c, c, furrow, made by a water-insect, crossing the footprint (x) at d; at e the furrow' enters a gallery, of which the roof has been broken; at f it becomes a tunnel or gallery, with convex roof, such as seen also at b, b; g, g, small galleries; h, h, furrows; i, i, holes; k, k, shell of a Linnæus; m, m, a furrow-track.
The occurrence of the eggs of insects in the Mexican travertine,
