1: Bio class setting

4: Monorail unit

8: Resistance units

12: Head hunters?

13: Golfer Irwin

14: True to the cause

16: Galley propellers

17: Pat oneself on the back verbally

18: Do a one step

19: Peevish states

21: They get into sushi

23: Autumn tool

24: Small amount

25: Glasgow girl

27: Lowlife

29: It can be a sacrifice

30: 'Hee ___'

31: Peaty place

34: In league

37: Fibula or femur

38: Temple student

39: Rioter's illegal take

40: Cockroach, for one

41: ___ cheese

42: Droop

43: Fossey's focus

45: Most withdrawn

47: Pindar product

48: Wrinkly-faced canine

49: Cardinal

50: 28,800 seconds before midnight

51: Mr. Peanut accessory

52: Not masc.

55: Football's contour

58: Course of action

60: Warehouse

62: Greek hymnist

64: Like the Atacama

66: Spoken

67: Obsolete repro

68: Gaucho's cattle catcher

69: Naval post?

70: Medicinal amount

71: Delight, as a comedy club crowd

72: Tournament exemption

1: Jungle vine

2: Caustic

3: Gold medal-winning

4: Pot ingredient?

5: Least well done

6: Juicy plants

7: Whimper

8: Trite

9: Survivalist's stash

10: Talking bird

11: Give the ax to

12: Popular ABC adventure series

15: 'I'm Sorry' singer Brenda

20: Turn on an axis

22: Read quickly

26: 'Not only that ...'

28: Electrify

29: Byte fraction

30: Not share

31: Tree trunk

32: Is short and shy

33: Oversupply

34: Besides

35: Put ammo into

36: Theater section

37: Commuter's option

40: Solicit alms

41: Container

43: Killer ___ (excellent computer program)

44: Well adjunct

45: Japanese honorific

46: Rushes

49: Yellow paper

50: Takes a powder

51: Christmas song

52: Sudden attack

53: Remove graphite or graffiti

54: Cheesy sandwich

55: Electrical unit

56: Not legally binding

57: BB's and bullets

59: Testing areas

61: Mausoleum

63: 'Sweet Pea' singer Tommy

65: One rotation of the earth