I just discovered these lyrics on The Scooby Site (http://hometown.aol.com/bdmnqr2/scoobystory.html); the words---by William Hanna, Joseph Barbera and Hoyt Curtin---to the one, the only, the original Scooby-Doo/Dynomutt Hour:

These three seasons would be syndicated as The Scooby Doo Show, with a modified Scooby-Doo/Dynomutt opening sequence (with references to Dynomutt removed. See below). The theme music was a total departure from the earlier "Scooby Dooby Doo" based themes, containing not even a reference to them, and further makes these seasons lack the feel of classic Scooby. Three later episodes, "The Menace in Venice", the "Beast is Awake in Bottomless Lake", and "Warlock of Wimbledon" were for some reason never syndicated, and after this last season would not be seen until a decade later, on cable.



The Scooby Doo Show--Syndicated/Cable (1980 to present):



We got it all together for a brand new show.
Scooby Doo is here again; away we go!
While Scooby Doo is runnin' from a spooky Ghost,
Shaggy is a-doin' what he does the most!
Hey come on, get involved, 'till the mystery is solved!
Hang around for Scooby Doo!



The Scooby Doo/Dynomutt Hour--Original (ABC, 1976):



We got it all together for a brand new show.
Scooby Doo and Dynomutt away we go!
While Scooby Doo is haunted by a spooky ghost,
Dynomutt is doin' what he does the most!
They make a super pair, with a super show to share:
Scooby Doo and Dynomutt!