Corn Snake Embryo (1 of 2) (image) Cell Press Share Print E-Mail Caption Corn snake embryo expression of the hindlimb/phallus gene Tbx4 (purple stain). Credit Carlos R. Infante Usage Restrictions Credit Required. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.