title: A block to cross-fertilization located in the egg jelly of the frog Rana clamitans.
mesh_terms: D000818:Animals; D001001:Anura; D047108:Embryonic Development; D005260:Female; D005306:Fertilization; D006824:Hybridization, Genetic; D008297:Male; D010063:Ovum / Q000502:physiology*; D011894:Rana pipiens; D011898:Ranidae; D013045:Species Specificity; D013084:Sperm-Ovum Interactions