This sweater is knit from wrist to wrist in one piece using a 16” circular needle. Matching hat pattern is included. Three sizes, from 6 mos. to 18 mos. Yardage requirements include enough for the hat as well.

Note that the errata link is for a PDF download for the desired issue as part of a set.

From the Errata
Mexicali Baby Ole, p. 72.
Yardage required in vitals: 459 (550, 650) yds.
Measurements: B 9 1/2 (10 1/2, 11 1/2) C 10 1/2 (11 1/2, 12 1/2).
Front Neck Shaping (Cast on rows): For size 18 mos, cast on …2 sts 3 times (instead of 2 times). Stitch count is 69 sts (instead of 59 sts). Left Sleeve (Dec rows): Dec 1 st each side…every 4th row 8 (6, 4) times (instead of 7 (5, 3) times).
A clarification: For a shorter collar, try working 2 additional stitches on each short row, instead
of just one.