1: Bio class setting

4: Monorail unit

8: Quarter fraction

12: Bona ___

13: Whip mark

14: Viva voce

16: Buddhist leader

17: Keeps from squeaking

18: Part of MGM

19: Squadrons

21: Word before opera or dish

23: Lady's man

24: Take one's cuts

25: 'That was close!'

27: Piano man Charles

29: 'Aquarius' musical

30: Not against

31: Winter ailment

34: Some ''Soul Train'' line maneuvers

37: Luxuriate at the beach

38: Trucker's ride

39: Given the ax, with “off”

40: Otherwise

41: Hew

42: Point, as a rifle

43: Responsibility

45: '___ in Pink' (1986 movie)

47: Two-piece piece

48: Solicit alms

49: Marking float

50: Byte fraction

51: Tear apart

52: Zoological duct

55: Talking bird

58: Whiskey measure

60: Historic river of Paris

62: Almost eternity

64: Multigenerational story

66: Musical pitch

67: Island near Molokai

68: Upgrade the decor

69: Stumblebum

70: Household staff

71: Girls' books hero Nancy

72: Grass in a loft

1: Jungle vine

2: Let on

3: Lick

4: Slam dunk point count

5: Aggressive poker player, say

6: Give permission for

7: City near Scottsdale

8: Video recorder, for short

9: Pensive piece of poetry

10: Memo

11: Chance to play

12: Bollux up

15: Morse code component

20: Tiff

22: Lions and Tigers and Bears

26: 'To each ___ own'

28: First zoo?

29: Buried

30: Jack Sprat no-no

31: Neck line?

32: Spirited air

33: Really hard on the eyes

34: Hunk of cheese

35: Weak poker hand

36: Peru's capital

37: Commuter's option

40: Cockroach, for one

41: Whimsical

43: 'Shogun' sash

44: Takes home

45: Groaner

46: Fishing gear

49: Happen

50: Old hat

51: Rodeo competitor

52: String quartet member

53: Get one's goat

54: Watermelon beginning

55: ___ de mer (seasickness)

56: 'You betcha!'

57: What the fourth little piggy had

59: Bunch of bulls

61: Inscribe with acid

63: Nurse, as a zombie

65: She's got milk