Batman's original costume featured a rounder mask with ears pointing out at angles, a round belt buckle and short gloves which did not extend past his wrists.
from "Case of the Chemical Syndicate" by Bill Finger and Bob Kane- Detective 27
By Detective 36 the costume had been standardized with a much more flowing cape that looked less like wings and a square belt buckle.  The ears extended straight up and well above the top of his head.  Beginning in this issue, Batman wore his special gloves with the spines (or whatever they are) up the sides.

 from "Professor Hugo Strange" by Bill Finger, Bob Kane and Jerry Robinson. Feb. 1940

by Detective 43, Batman's ears were placed much lower on the sides of his cowl, giving him the look that would remain standard until the 1960's.

from "Case of theCity of Terror" by Bill Finger, Bob Kane, Jerry Robinson and George Roussos,  Detective 43, Sept 1940.