(c) The internal openings of the nostrils.
(d) The single opening of the Eustachian tubes. [In the Frog there is an opening on each side.]
(e) There is no tongue. [A tongue is present in the Frog.]
(f) The glottis.
(g) The gullet.
Owing to the complexity of the Eustachian tubes and the bony form of the ear cavity, it is not possible to pass a seeker from the Eustachian aperture through the tympanic membrane. [In the Frog the Eustachian tubes are short and straight and permit of this being done.]
Fig. 2.—Mouth cavity of Xenopus and Rana.
Muscular System and Vascular System (Part).
1. Pin the Platana on its back in water, and cut through the skin with scissors along the middle line, throughout the whole length of the body. Pin back the skin on each side, and make a drawing showing:—