Evolution of the cochlea about 7 mm long. Like in lepidosaurs and archosaurs, it contains a lagena, a vestibular sensory epithelium, at its tip. Only in therian mammals (marsupials and placentals) is the cochlea truly coiled 1.5 to 3.5 times. Whereas in monotremes there are many rows of both inner and outer hair cells in the organ of Corti, in therian (marsupial and placental) mammals the number of inner hair-cell rows is one, and there are generally only three rows of outer hair cells. Amphibians have unique inner ear structures. There are two sensory papillae involved in hearing, the basilar (higher frequency) and amphibian
Jock Stirrup Jock Stirrup Marshal of the Royal Air Force Graham Eric Stirrup, Baron Stirrup, (born 4 December 1949), informally known as Jock Stirrup, is a former senior Royal Air Force commander who was the Chief of the Defence Staff from 2006 until his retirement in late 2010. He is now a Crossbench member of the House of Lords. In April 2013, he was appointed a Knight of the Order of the Garter by Queen Elizabeth II. As a junior RAF officer, Stirrup was a jet pilot, and saw action in the Dhofar War. Later in his career, he commanded No. 2