Errata

Instructions as published should have been marked “Right Hand Mitt”

Rnd 6: 1ch (does not count as st throughout), 7dc, 1ch, miss 8 sts (thumbhole made), 20dc, join with sl st in first st – 27sts.
Rnd 7: 1ch, 1dc in each st around working 1dc in 1ch-sp from prev rnd, join with sl st in first st – 28 sts.
Rnd 8: [2ch, 1tr in next st] (counts as tr2tog), 2ch, miss 2 sts, 14tr, [2ch, miss 2 sts, tr2tog] twice, 2ch, miss 2 sts, join with sl st in top of first tr2tog – 17 sts, 4 2ch-sps.
Rnd 9: 1ch (does not count as st), 1dc, [3dc in 2ch-sp from prev rnd, miss 1 st] four times, 13dc, [miss 1 st, 3dc in 2ch-sp] three times, join with sl st in first st – 25 sts.

Then instructions for the Left Hand Mitt are as follows:

Using yarn A and 4mm hook, make 31ch.
Row 1: 1dc in second ch from hook, 1dc in each ch to end, turn – 30 sts. 
Row 2: Sl st in first 5 sts, 3ch (counts as 1tr throughout), 24tr, turn – 25 sts.
Row 3: 3ch, 1tr in st at base of 3ch, 24tr, 6ch, sl st in third ch of 3ch from beg of row to join in the round – 26 sts.

Working in rnds, cont as folls:
Rnd 1: 3ch, 25tr, work 5tr around 6ch from prev row, join with sl st in third ch of 3ch – 31 sts.
Rnd 2: 3ch, 18tr, 2tr in next st, 11tr, join with sl st in third ch of 3ch – 32 sts.
Rnd 3: 3ch, 19tr, 2tr in next st, 11tr, join with sl st in third ch of 3ch – 33 sts.
Rnd 4: 3ch, 20tr, 2tr in next st, 11tr, join with sl st in third ch of 3ch – 34 sts.
Rnd 5: 3ch, 21tr, 2tr in next st, 11tr, join with sl st in third ch of 3ch – 35 sts.
Rnd 6: 1ch (does not count as st), 16dc, 1ch, miss 8 sts (thumbhole made), 11dc, join with sl st in first st – 27 sts.
Rnds 7–10: Work as Right Hand Mitt.

Instructions for edging and finishing as given are correct for both mitts.