Unprinted mail order pattern of unknown branding. This particular one is a size 2, but it was available in even sizes up to 10. Dress has abbreviated sailor collar, T yoke, princess seaming, and matching panties and sailor hat. Would lend itself well to two-tone construction. It also has both long sleeved and a short sleeved versions.
From the style of it, I would say it's a 1940s or even 1930s pattern, but I can't be sure. The dress buttons down the front, and the instructions recommend both french seaming and bound buttonholes.
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