1887.] IN THE LARYNX OF THE ANUROUS AMPHIBIA. 501 



If the apparatus be held to be of none but physiological significance, 

 the clue to its meaning has yet to be found ; it is clearly in no way 

 associated with the development of the vocal sac, nor is it confined to 

 the males, as might be supposed. In the higher forms, however, it 

 is vestigial and of little or no functional importance; and there is 

 nothing forthcoming in any one specimen which is not represented in 

 the male of Chiroleptes. These facts, in view of the uniformity of 

 development of the parts in the latter, would seem to me to suggest 

 that the apparatus has an important morphological significance, and 

 that in the admittedly lowly Australian type the primitive condition 

 is most nearly exemplified. The problem is an interesting one, and 

 further investigation is necessary for its solution. 



Turning, finally, to the question of general morphological import- 

 ance, it is clear that the discovery of the epiglottis in the Amphibia, 

 in the form and under the conditions here recorded, carries back a 

 stage i'urther the initiation of one more structure peculiarly charac- 

 teristic of Mamriials. The interest of this is increased when we 

 reflect upon the identity of the Amphibian epiglottis, which is 

 clearly bilaterally symmetrical, if not actually paired, with the initial 

 pliase in development of that organ in the human subject as observed 

 by His. The facts show that the origin of this typically Mamma- 

 lian structure must be sought in animals lower than the living 

 Lizards'. It would be wide of the mark to form data for discussing 

 the question of Mammalian afliinities upon it. In view, however, 

 of the anticipation of the csecum coli in the Common Frog^, and of 

 the excursions made by those Amphibia with suppressed larval meta- 

 morphoses^, iu which it is highly probable there may have been 

 foreshadowed the foetal membranes of the Amniota (c/. Huxley, 

 P. Z. S. 1880, p. 660), the facts here recorded can best be regarded 

 as in( icative of similar excursions towards the elaboration of the 

 voice-organ, anticipatory, as has been shown, of the characteristically 

 Mamnialian condition. 



^ It is of interest here to note the existence of an epiglottis-like flbro-carti- 

 laginous plate in Frotopterus. Attention was first di'awn to it by Heule {I. c. 

 pp. 5, 6), and it was shortly afterwards described in full and figured by Biseboff 

 (" Descr. Anat. du Lepidosiren parado.va,''' Ann. Sci. Nat. t. xiv. Zool. 1840 

 p. 136). Wiedersbeim has refigured it (' Lebrbucb ') and recorded {ibid.) the 

 disco^e^y of an analogous structure in Lcpidosfeus. 



^ Huxley, in Huxley aud Martin's Elem. Biology, 1875, p. 166. 



^ 'Especially Koto^rcnia, Weinland, Archiv f. Anat. und Phys. 1854; Hylodes, 

 Peters and Gundlacb, Monatsb. Beilin. Acad. 1876 ; Rana opisthodon, Boulenger, 

 T. Z. S. \ol. xii. 1886 ; Phyllomedusa, v. Ibering and Boulenger, Ann. & Mag. 

 Nat. Hist. vol. xvii. 1886. 



For a resume of tbe subject generally, with full references and list of species, 

 see Boulenger on I'hyllomedusa, op. cit. p. 464. Cf. also Smitb and Cope on 

 Dendrobatvs, Amer. Naturalist, 1887, pp. 307-311. 



