Yes, the Constitution originally had legislatures appointing senators.
Back in the late 18'th century, the Founding Fathers did not always trust direct elections, due to logistics. Many people didn't understand the issues with communications almost negligible, so the Founding Fathers created the Senate as a check against the popularly-elected House. It was not until communications became easy enough that campaigning was possible that direct elections of senators was approved by amendment.
The House had small enough districts that campaigning was practical, but statewide or national elections were a completely different matter as no forms of electronic communications were available and the fastest mode of transport was the horse. The small districts permitted popular elections.
Keep in mind that the Founding Fathers always assumed a citizen legislator, who would serve for a short time and then go home, so they never envisioned a professional politician class who had time to campaign for two straight years.
Of course, a second reason for the Senate was the Connecticut Compromise where the smaller states were afraid of the power of the large states, so while the House was apportioned based on population, all states had two senators regardless of size.
A similar reason was behind the Electoral College as insulation against a direct popular vote.
