188/.] IN THi; LARYNX OF THE ANUROUS AMPHIBIA. 493 



hinder border of the body of the hyoid. This was so in the specimen 

 to which I have just referred, and the anterior prolongation described 

 overhung this depression, in a manner strikingly suggestive of the 

 epiglottis. 



HoU ' and Royer and Bambecke^ have most recently studied the 

 anatomy of the mouth in tlie Anurous Amphibia : the first-named 

 author deals chiefly with histological details in R. temporaria ; tiie 

 last-named deal with the subject in general ; but i fail to find 

 mention, in their writings, of those facts with which I am concerned. 

 I am satisfied that the structures described abo\e may or may not 

 be present in individual examples of the common Frog, and iiave 

 found, to my surprise, that the free anterior extremity of the larynx 

 is subject to no inconsiderable amount of variation in it, to say 

 nothing of the Anura as a group. 



If tlie H|is of the laryngeal aditus be examined with care in 

 R. temporaria there will generally be found at its anterior end folds 

 identical with those here figured, but more or less n;arked. They 

 are sometimes so small that there is little wonder they should have 

 been so long overlooked. They are well ditJVrentiated from the rest 

 of the larynx ; of a yellowish colour in life and soft and fleshy, pro- 

 jecting freely beyond those parts which are supported in cartilage 

 (c/. tigs. 1, 1 </, ey). There generally passes between them a thin 

 transverse fold of mucous membrane, and occasionally, when very 

 minute, they are, together with the same, erected and closely applied 

 to the front face of the larynx (figs. 1 b and 6). I was for some 

 time disposed to think that they might be peculiar to the males; 

 but that this is not the case the larynx of an adult female, repre- 

 sented hi fig. 1 c, will show. That specimen is furtiier remarkable, 

 among the larynges of a number of females which I have examined, 

 for the fact that the folds were continued along the sides of the 

 aditus, the anterior half of that being thus embraced by a hood- 

 shaped lip. 



On examining other members of the group, it early became obvious 

 that the structure with which we here have to deal was by no means 

 exceptional. In Leptodactylus pentadactylus and the Bull-Frog 

 {R. jjijiieii.s), for example (figs. 2 and 3), two papillate elevations were 

 found to be present ; these were in both cases small and erected, and 

 united by a transverse fold as in the first-named example. Compa- 

 rison of figs. 1 b and 2 reveals an absolute identity between indivi- 

 duals of R. temporaria and Leptoc/actylus pentadactylus. 



In two of the above-named species 1 found, in addition to the fore- 

 going, a couple of other folds which were related to the hind half of 

 the aditus {ep, figs. 2 and 3). In the Bull-Frog (fig. 3) they 

 passed insensibly into the mucous membrane posterior lo the larynx ; 

 but in Leptodactylus (fig. 2) they united behind so as to form an 

 insignificant lip which enj braced the hind boundary of the aditus, 

 much as did the supposed epiglottis its front one. I have not seen 



1 Sitzuugsb. Wien. Akad., Jan. 1887. 



• " Sur les caract. fournis par la bouche des tStards des Eatraciens auoures 

 d'Europe," Bullet. Soe. Zool. d. France, 1881, p. 75. 



Pkoc. Zool. Soc— 18S7, No. XXXIII. -33 



