The Mammalian presternum (manubrium sterni) and xiphosternum have the same origin as the main body of the sternum (Ruge, No. 438).
The manubrium, or handle, is also the centre of a nerve-system.
The nectocalyx is now somewhat drawn together in persistent systole, with the manubrium and tentacles strongly retracted.
The loss of time, however, appears to take place in the manubrium itself, where the rate of response is astonishingly slow.
Probably in many mammals the manubrium will be found to be partly made up of corresponding rudiments.
If the irritation be slightly stronger, all the four tentacles, and likewise the manubrium, contract.
The wound on the neck was approximately an inch and a half above the manubrium of the sternum, the sternal notch.
Accordingly, I cut off the manubrium, and tried stimulating its own substance directly.
The sternum is much wider than long, and no specimens give evidence of a manubrium.
In all the species both of Sarsia and Tiaropsis, the manubrium and tentacles are retracted during exposure to this poison.
manubrium ma·nu·bri·um (mə-nōō'brē-əm, -nyōō'-)
n. pl. ma·nu·bri·a (-brē-ə)
The upper segment of the sternum with which the clavicle and the first two pairs of ribs articulate.
The portion of the malleus that is embedded in the tympanic membrane and extends downward, inward, and backward from the neck of the malleus.