It is, of course, uncertain to which of the several herons occurring in Central America these representations refer. Possibly the Great Blue heron (_Ardea herodias_) or the Louisiana heron (_Hydranassa tricolor ruficollis_) is intended. It seems not unlikely also, that one of the white egrets may be shown as their crests are fairly conspicuous. FRIGATE-BIRD (_Fregata aquila_). We have included here two figures (Pl. 15, figs. 8, 9) that undoubtedly represent a single species of bird. It is characterized by a deeply forked tail and long beak, which has part way on its length, a circular object surrounded by a circle of dots. It seems still problematical what this object may be. In one figure (fig. 9), the beak is strongly hooked, in the other (fig. 8) it is straight, but as the latter is plainly a much more carelessly made drawing, we may infer that the hooked bill is more nearly correct. This would exclude the Terns (_Sterna_), to which Stempell has referred the figures. It seems probable that the frigate-bird (_Fregata aquila_) is the species intended, as this is not only a large conspicuous form on these coasts, but it has a long and strongly hooked beak and forked tail. The length of the beak would probably exclude from consideration, the swallow-tailed kite that also occurs in the region. Both these birds are pictured, evidently as an offering or sacrifice. It is very seldom that the whole bird is represented in this connection, and still more infrequent to find anything but the turkey, which is the usual bird of sacrifice. The figure from the Dresden Codex (Pl. 15, fig. 9) rests upon the usual bowl or jar, that from the Tro-Cortesianus (Pl. 15, fig. 8) is pictured upon a grotesque animal head, three _Kan_ signs and these upon the jar. In the Tro-Cortesianus 20c, 21c, there occur several representations of man-like forms with very peculiar heads. The latter are each provided with a beak-like projection, on which appears the circle surrounded by dots noted above in connection with the frigate-bird. Brinton concludes that this mystic symbol is a representation of the curious knob on the bill of the male white pelican, and therefore identifies these curious figures as pelicans. Stempell follows Brinton in this, but considers that they are the brown pelican (_P. fuscus_), since the white pelican is rare or casual, as far south as Yucatan. Unfortunately, however, for this supposition, the brown pelican lacks the curious knob that Brinton believed to be represented by the circle of dots. Moreover, this same sign occurs on the drawings of the bills of the frigate-bird and the ocellated turkey, and is evidently not of specific significance. To our minds it is doubtful if the figures under discussion are birds at all, and we are unable to assign them a name with any degree of confidence. A peculiar glyph occurs in connection with them which may be an aid to their ultimate identification. Brinton calls the glyph the "fish and oyster sign."