Crossword: ''Four Legs Good''

Across
1 There's one at the beginning of each of this puzzle's four theme entries
7 Retail estab.
10 Holder and Reno, for short
13 "Nets to Catch the Wind" poet Wylie
14 Goneril's father
15 Sign for a packed theater
16 Getting gray
17 Ways out
19 Sketch show with Dollar Bill Montgomery
20 Bart Simpson word
21 Gothic novelist Radcliffe
23 1 of 18
24 Explorer with a peak named after him
29 C times C, divided by IV
32 Chef who says "Pork fat rules!"
33 Had some hash
34 Type of 1-across, in Mexico
35 Burn in the tub
36 Election Day day: abbr.
37 Leader of 1960s UK rockers The Pacemakers
38 Till compartment
39 ___ Harbour, Fla.
40 Shown past the foyer
41 "What is it?"
42 Native American group (and source of a Washington city that differs by one letter)
44 Yell on the links
45 Pop-up blockers block them
46 Drug abused by Rush Limbaugh and Courtney Love
50 Like growly stomachs
55 Removed from the actual action, as with a commentator
56 Where Cedric the Entertainer got a big break
57 ___ chi
58 Jimmy Eat World's "Drugs ___"
59 "I thought it'd never get here!"
60 Damascus's place: abbr.
61 Lofty poem
62 Notable feature of each 1-across