288 H. H. WILDER 



gives the arytaeuoids the position shown best in Figs 34 — 35. The 

 angle formerly the farthest ventral is now anterior while the dorsal 

 angle is posterior. The change is, however, best shown by the apical 

 cartilages which now take a^ median position on the pharyngeal sur- 

 face (Fig. 34). The vocal chords are rotated also and lie parallel to 

 the longitudinal axis of the body (Fig. 35). The annulus is affected by 

 this rotation on account of the close connection of the cardiac processes 

 with the arytaenoid. By means of this its cardiac side is carried ante- 

 riorly thus rotating the plane of the entire ring though in less degree 

 than in the case of the arytaenoids. Similar modifications take place in 

 the position of the muscles. That this rotation is a real one and 

 not fancied I have proven by the development. In young frogs of 

 this type (R. clamitans) with four legs and a caudal stump of 

 2 — 3 cm, the arytaenoids still lie in the position of the first type 

 with the apical cartilages directed anteriorly. 



Type III. This type like the first has only one representative, 

 B. esculenta, but it is this particular form which is figured in Ecker 

 and Wiedersheim's Anatomie des Frosches (No. 3) and which has 

 consequently been copied in all the text-books as the typical larynx 

 of Bana. As a matter of fact this form is entirely unique and I 

 have failed to find in my other species a similar condition. The 

 rotation is the same as in the second type, but a farther modification 

 has taken place through the fusion of the two bronchial processes 

 across the median line to form a fantastically shaped W. Aside 

 from this the other parts of the annulus are extremely delicate and 

 gracefully looped, giving one at first the impression of an entirely 

 aberrant form. By comparison of Fig. 44 with Fig. 35 the real 

 cause of the difference becomes apparent. 



6. Bu/o. 



The disposal of the cartilages here reminds one at first of Alytes 

 especially the excessive development of the bronchial processes, which 

 show at their free end some of the irrigularities characteristic of the 

 bronchial ends of the tracheal pieces in the Urodela (compare 

 Figs. 25 and 26 with Fig. 43). The annulus is here complete and 

 consists of a simple ring almost without processes. This reduction 

 may be considered as secondary through the evidence of the muscles 

 which show a reduction from the frog type. Most important in this 

 respect is the complete disappearance of the anterior pharyngeal pro- 

 cesses together with those elements of the intrinsic muscular ring 



