1. Comparing the skin and body color, the frog has two longitudinal wrinkles from the back of the eyes to the base of the hind limbs, which are golden yellow or light brown. There is a light vertical stripe in the center. There are many horizontal black markings on the hind limbs. The frog's back is brown or yellow-green, and its belly is white. The toad has rough skin and its body is densely covered with wart-like protrusions of varying sizes. The back is dark brown and the belly is creamy yellow.
2. Observe the venom glands. Toads have abundant venom glands, which are divided into skin glands and postauricular glands. Skin glands are distributed on the back of the body, and the epidermis where they are located is locally thickened into "warts." The postauricular gland is located above the tympanic membrane on the side of the head. Carefully prick the postauricular gland with a needle, and milky white toxic serous fluid will flow out. Frogs don't have venom glands.
3. Observe the vocal sac. There is a pair of vocal sacs behind the mouth corners of male frogs. When making sounds, the gas in the mouth presses into the vocal sacs, causing them to expand into a spherical shape. Female frogs do not have vocal sacs. Neither male nor female toads have vocal sacs.
4. Comparing Teeth and Tongue: There is a row of tiny maxillary teeth on the edge of the frog's upper jaw; there are also two rows of small, tumor-like protrusions running side by side on the vomer bone at the top of the mouth, called vomerine teeth. The toad has no teeth in its upper and lower jaws. Pull out the frog's tongue. The tip of its tongue is forked; the tip of the toad's tongue is not forked.
5. Observe the connection between the ureters and the cloaca. The two ureters of the frog are connected to the cloaca respectively, and have two openings on the cloacal wall; while the two ureters of the toad first merge into a common ureter, and then enter the cloaca, with only one opening on the cloacal wall. .
6. Observe the connection between the fallopian tube and the cloaca. The two fallopian tubes of frogs are also connected to the cloaca respectively; while in toads, they merge first and then connect to the cloaca.