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 – Iraq. Stirrup strongly backed Mohan's plan but noted that Mohan would need to be pressed hard to deliver and also supported with Corps forces. Austin was reluctant to provide support, wishing to focus on Mosul, but Petraeus agreed with Stirrup. However, this plan was overtaken by Maliki's decision to launch Operation Charge of the Knights. Both Stirrup and the American commanders were taken by surprise and were concerned about the lack of planning but Maliki was determined to launch his operation in late March. Operation Charge of the Knights led to the Battle of Basra which lasted from 25