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Show 498 PROF. G. B. HOWES ON AN UNRECOGNIZED FEATURE [June 7, it (figs. 6 to 10) in all its important aspects. The interest of vastly increased when it is stated that in a female which I have examined the folds were absent, while in a second male they were insignificant'-facts which point to the conclusion that their development takes place comparatively late in life, in all probability corre-latively with sexual maturation. The larynx in Chiroleptes australis, side view. The same, in longitudinal section. References as in previous figures, ca, right arytenoid; c.lt, cricoid (laryngotracheal) cartilage; hy, body of hyoid ; mgh, genio-hyoglossus muscles ; pc, pericardium; pl, entrance to right lung; s.g, gular sac; VO, right vocal cord. Figs. 6 to 9 will show how fully the two structures may be developed. The epiglottis, eg., stands out prominently in front; the epilaryngeal fold is hood-shaped, overhanging the hinder third of the aditus, and the two together embrace the lateral walls of the aditus for nearly its whole extent-so much so, that I at first took them to be continuous. This, however, is not the case, and here, as in all other examples with which I have met, the two structures, although they may approximate, are perfectly distinct (cf. fig. 5). The epilaryngeal fold is entirely membranous, exhibiting on its upper part, which is 1 For tho opportunity of examining these two specimens, as for further assistance, I a m indebted to the courtesy of M r . Boulenger, F.Z.S., of the National Museum at South Kensington. |