Designed locally in Brenham, TX. 
The bust is measured from underarm seam to underarm seam across the front.  Double to get the circumference.  The length is measured from the shoulder seam down to the hem.
 
 Small:  Bust is  19" (38" around);  Length is 26"
Medium: Bust is 20.5" (41" around); Length is 27"
Large: Bust is 22" (44" around); Length is 28"
X-Large: Bust is 24" (48" around); Length is 28"
2X: Bust is 26" (52" around); Length is 29" 
3X: Bust is 27" (54" around); Length is 30"