The teponaztli was a cylindrical block of wood hollowed out below, and on its upper surface with two longitudinal parallel grooves running nearly from end to end, and a third in the centre at right angles to these, something in the shape of the letter I. The two tongues left between the grooves were struck with balls of rubber, ulli, on the ends of handles or drum sticks.  These instruments varied greatly in size, some being five feet in length, and others so small that they could conveniently be carried suspended to the neck.  The teponaztli was the house instrument of the Nahuas.  It was played in the women’s apartments to amuse the noble ladies, and the war captains carried one at the side to call the attention of their cohorts on the field of battle (Sahagun).  The word is derived from the name of the tree whose wood was selected to make the drum, and this in turn from the verb tepunazoa, to swell, probably from some peculiarity of its growth.[29]

A much superior instrument to the teponaztli, and doubtless a development from it, was the tecomapiloa, “the suspended vase” (tecomatl, gourd or vase, piloa, to hang or suspend).  It was a solid block of wood, with a projecting ridge on its upper surface and another opposite, on its lower aspect; to the latter one or more gourds or vases were suspended, which increased and softened the sound when the upper ridge was struck with the ulli.[30] This was undoubtedly the origin of the marimba, which I have described elsewhere.[31]

The musical properties of these drums have been discussed by Theodor Baker.  The teponaztli, he states, could yield but two notes, and could not have been played in accord with the huehuetl.  It served as an imperfect contra-bass.[32]

The omichicahuaz, “strong bone,” was constructed somewhat on the principle of a teponaztli.  A large and long bone was selected, as the femur of a man or deer, and it was channeled by deep longitudinal incisions.  The projections left between the fissures were rasped with another bone or a shell, and thus a harsh but varied sound could be produced.[33]

The tetzilacatl, the “vibrator” or “resounder,” was a sheet of copper suspended by a cord, which was struck with sticks or with the hand.  It appears to have been principally confined to the sacred music in the temples.

The ayacachtli was a rattle formed of a jar of earthenware or a dried gourd containing pebbles which was fastened to a handle, and served to mark time in the songs and dances.  An extension of this simple instrument was the ayacachicahualiztli, “the arrangement of rattles,” which was a thin board about six feet long and a span wide, to which were attached bells, rattles and cylindrical pieces of hard wood.  Shaking this produced a jingle-jangle, agreeable to the native ear.  The Aztec bells of copper, tzilinilli, are really metallic rattles, like our sleigh bells.  They are often seen in collections of Mexican antiquities.  Other names for them were coyolliyoyotli. and