Figures of a crocodile (_Crocodilus americanus_) are frequent in the Nuttall Codex, where there is one large figure of the entire animal (Pl. 13, fig. 8), making its way along under water. It is shown with numerous dorsal spines, a long tail, and powerful claws. Curiously, however, it has no lower jaw and the same is true of the numerous glyphs representing the head of the animal. This is so pronounced a characteristic, that it may be doubted if the open-mouthed head and the single limb shown in Pl. 13, fig. 2, really picture the same animal, though otherwise apparently referable to the crocodile. In the various glyphs showing the head of this species, the prominent, elongate eyebrow and the absence of the lower jaw are noteworthy points, while the teeth may vary in number from three to six. The glyphs (Pl. 13, figs. 1, 3-7) represent the Nahua day sign _Cipactli_ corresponding to the Maya day _Imix_. In the band of constellation signs in Dresden 52b (Pl. 13, fig. 10), there occurs a single figure with a long curled eyebrow and lacking the lower jaw. In the upper jaw three teeth are indicated. A comparison of this figure with the glyphs in the Nuttall Codex seems to leave little doubt that it represents a crocodile. This is the sign which Förstemann (1906, p. 206) interprets as standing for Saturn. Pl. 13, fig. 12, is certainly the same sign as it stands in relatively the same position in the constellation band on Dresden 53a. It represents the highly conventionalized head of a crocodile. On Stela 10 from Piedras Negras (Maler, 1901-1903, Pl. 19) the same glyph is seen. The range of the alligator in North America does not extend to Yucatan, hence the crocodile, which does occur there, is taken as the original of all these figures. There is nothing in the latter that would distinguish it from the alligator. TURTLES. Representations of the turtle (Maya, _ak_) are not uncommon among the Mayas. At Uxmal there is a ruined building called _Casa de las Tortugas_ on which at intervals around the cornice there are carvings of turtles. Turtles of at least two species occur in the Tro-Cortesianus. With one exception, they seem to be limited to this codex. That shown on Pl. 14, figs. 1-3, 5, is a large species with the dorsal scutes represented by large diamond-shaped pieces. There is little that might be considered distinctive about these turtles, although one (Pl. 14, fig. 5) has the anterior paddles much larger than the posterior, indicating a sea turtle. What is doubtless the same turtle is pictured in several places in the Nuttall Codex. In one of the figures in the latter manuscript, the shell is shown apparently in use as a shield (Pl. 14, fig. 4). This would indicate one of the large sea turtles, and there is not much doubt that either the Loggerhead turtle (_Thalassochelys cephalo_) or the Hawksbill (_Chelone imbricata_) is here intended.