ACROSS

 1 One can get a rise out of this, but to a degree a ruler gets what one might take in a hurry. (6,6)

10 It could be the worker to carry what looks like an aardvark. (3,4)

11 and 4 down Red-head? (7,9)

12 State the responsibility of Mario! (5)

13 Do they get paid regularly in auntie’s establishment? (9)

14 Sends on the receipts–even if they don’t go over the water. (10)

16 "Turnpike" might describe it, if you take military cover. (4)

18 The Walrus and the Carpenter had to give a hand to this. (4)

20 What the "spy in the sky" is supposed to be doing? Or one like Simon Legree? (10)

23 Getting along socially? That’s where a butterfly might help! (2,3,4)

25 Ishmael’s mother, with a garland to show her off. (5)

26 Everything in a wild ride describes one who fools around! (7)

27 Early lutanist and composer of "The Wise Old Owl and Me." (7)

28 Where we sent mail to GIs, to add to the dental trouble caused by drug handlers. (12)

DOWN

 2 A female singer on a get-together in Pennsylvania. (7)

 3 Igloo? (3,5)

 4 See 11 across

 5 The founder of a Turkish dynasty–one of Morocco’s many. (5)

 6 Sounds like Little Richard more than once found a little antelope! (3-3)

 7 Part of the area Liz established, as one might find out. (7)

 8 When amateur ornithologists do, it’s because one is spotted, according to a signal from the camera operator. (5,3,5)

 9 Somewhat dated description for one of "two on the aisle." (8,5)

15 Unnaturally rapid, came to help in an emergency, perhaps. (9)

17 This location in Pakistan is in bad shape, with the fighting going on! (8)

19 Tom on one of the Swiss hills, with a tree here. (7)

21 One wouldn’t thank you for showing where to start the fire! (7)

22 In Rome, perhaps, or in Spain you might have found such a sheep originally. (6)

24 The merit of a wild throw? (5)