a, Fore limb buds (FL) and b, hind limb buds (HL) of mouse and the three-toed jerboa, Dipus sagitta, at 10.5, 11, 11.5, 12, and 12.5 dpc. c, Fore limb and hind limb of the five-toed jerboa, A elater, at approximately 12.25 dpc. d, Fore limb and hind limb of the horse at 30 dpc (approximately equivalent to mouse 12 dpc). e, Fore limb and hind limb of the camel at 38 dpc (approximately equivalent to mouse 12.5 dpc). Scalebar = 1 mm for D sagitta, A elater, horse, and camel and 0.8 mm for mouse limbs.