Times 25323 help with word play

[Huddle]

Can someone help with wordplay for these 3 clues. Mulled on it overnight and still cannot get it. Thanks in advance.
15a cat's fate, to keep working with single tongue. Monoglot. Get the single tongue!
21a bound to turn over stone of delicate colour. Baetyl is stone
17d Cupid flies about only a few feet, that's very clear. Pellucid. Anag of Cupid about??

[factor-fiction]

http://en.wikipedia.o..._units_of_measurement
ELL is a distance

[factor-fiction]

Cat is MOG if that helps

[factor-fiction]

Mog's lot?

[sandyRoe]

ell is, or was, a measurement. letters of 'cupid' and ell

[Huddle]

Thanks - you learn something new all the time.

[bibblebub]

15a) cat = MOG, fate = LOT, working = ON => MonOG log

21a) PASTEL = delicate colour
bound to turn over = leap reversed = PAEL, stone = ST => PAstEL

[bibblebub]

(sorry about the typo at the end of the 1st line)

[SadOwl]

21a PASTEL - LEAP around stone (st = stone as in weight) reversed.

[Huddle]

That makes more sense. Thanks a lot bibblebub

[SadOwl]

Sorry, bibblebub obviously types faster than me!