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		In a second experiment, both hindlimb and forelimb grafts were able to form cartilage, but again developed primarily distal structures compared to control embryos (fig. 8) Figure 8. Cartilage development in 5-day chick limbs grafted on the chorioallantoic membrane. Discussion The results of this experiment suggest that cartilage formation is possible in limb grafts, but that cartilage formation is maximal when the limbs and chorioallantoic membrane are left completely intact in embryos.. Since limbs are capable of moderate cartilage formation when grafted onto the chorioallantoic membrane, the CAM is able to supply calcium to extraneous limb grafts through mere contact. These results suggest that the chorioallantoic membrane plays an active role in facilitating calcium transport for bone formation in chick embryos.