What is the definition of "Selav"?
Rashi: It is a fat bird called 'a quail.'
Why is "Selav" written with a 'Sin' and not with a Samech?
Yoma 75b: Because on the one hand, for the Resha'im, it felt like a thorn (Silon) in their throats, whereas the Tzadikim ate it in tranquility ('b'Shalvah' - pronounced with a Shin). 1
See Torah Temimah, citing the Mechilta - which has a different version of the answer.
How will we reconcile this Pasuk, which writes that a layer of due fell on top of the Manna, with the Pasuk in The desert (11:9), which describes how the Manna fell on to a layer of dew?
Rashi: In fact, the Manna lay between two layers of dew, as if it was in a box, thereby keeping it fresh.
