Pony, Dugan

Usually seen in marigold and, to a lesser extent, in amethyst/purple ruffled bowls. Most bowls have six ruffles, but some have 10, as in the two shown here--and are a bit more desirable. Sixteen-ruffled bowls are also known. Ice cream shaped bowls are very rare, as are plates. Pony has been reproduced in plates and bowls. If a Pony piece is iridized on the bottom of the base, it is new. A lot have been showing up on eBay recently.
Bowls, 8 1/2 inches

Amethyst/purple, 85, 95, 100, 110 (all 2013),
   45, 155 (both 2014), 110, 130 (both 2015),
   70, 75, 90, 160 (all 2016)

Amethyst/purple, 10 ruffles, 575 (2009),
   120 (2013)

Aqua, 525 (2006), 480 (2009), 600 (2010),
   165, 350 (both 2014), 600 (2015),
   300, 525 (both 2016)

Ice green, 500, 525 (both 2011),
   900 (2012), 500 (2015), 750 (2016)

Ice green, 10 ruffes, 2,400 (2009)

Marigold, 20, 45 (both 2014),
   25, 30, 40 (all 2015),
   15, 25, 35 (all 2016)

Marigold, ice cream shape, rare, 600 (2015)

Vaseline/ice green, 825 (2004)

Ice cream shaped bowls are very rare in the Pony pattern. This dark marigold example is in the collection of Greg Dilian. I have records of only two others selling at auction in the last 20 years.

Updated 2/2/2017

Plates

The marigold plate below sold for $2,400 in 2002. It sold again in 2003 for $950. In 2002, amethyst and marigold plates sold for $110 each, the auctioneer stating that they were believed to be old. In 2006, a similar marigold plate brought $135 and in 2012 one brought $375. In 2015, a marigold plate, said to be old, brought $200. Buyers seem to be very skeptical of all plates.