Evolution of the cochlea of the ear, consisting of the scala media, the scala tympani, and the scala vestibuli. Regarding mammals, placental and marsupial cochleae have similar cochlear responses to auditory stimulation as well as DC resting potentials. This leads to the investigation of the relationship between these therian mammals and researching their ancestral species to trace the origin of the cochlea. This spiral-shaped cochlea that is in both marsupial and placental mammals is traced back to approximately 120 million years ago. The development of the most basic basilar papilla (the auditory organ that later evolved into the Organ of Corti in mammals) happened
Stirrup did not have stirrups. It is speculated that stirrups may have been used in China as early as the Han dynasty (206 BC–220 AD); however, verified archaeological evidence of stirrups in this period is scant. Stirrups were used in China at the very latest by the early 4th century AD. A funerary figurine depicting a stirrup dated AD 302 was unearthed from a Western Jin dynasty tomb near Changsha. The stirrup depicted is a mounting stirrup, only placed on one side of the horse, and too short for riding. The earliest reliable representation of a full-length, double-sided riding stirrup was