290 H. H. WILDER, 



in Äcris is so small that it scarcely shows in a pharyngeal view 

 (Fig. 51). In the males of Hyla, Hylodes and Choruphilus, the an- 

 nulus is reinforced by curved extensions of the thyroid processes of 

 the hyoid, rather thick and blunt in the two first, but so long and 

 tapering in Chorophüus that they give almost the appearance of a 

 second annulus. This is especially deceptive in cross sections. Sesa- 

 moid cartilages seem to occur in the tendons of the ring muscles 

 of all species, being absent in the females. In Hyla and in Choro- 

 philus I have demonstrated both anterior and posterior pairs (Figs. 50 

 and 54). They seem also to occur in Äcris. 



In addition to the above cartilages, I have succeeded in demon- 

 strating in the male Chorophilus a long and narrow pair which lie on 

 the cardiac side of the arytaeuoids in relation to the vocal chords. 

 These may be called accessory arytaenoids, and are shown in 

 the cross section Fig. 55. 



8. Bomhinator. 



This frog possesses a curious type of larynx, unique in itself, but 

 suggestive in comparison with the relationships met with in the Aglossa. 

 The most striking peculiarity, as seen in Fig. 45, consists of an 

 enormous expansion of the annulus, forming a broad resonance box, 

 at the top of which are situated the arytaenoids and the vocal chords. 

 The osseous thyroid processes of the hyoid closely enclose this re- 

 sonance box altough without actually participating in its formation, a 

 condition realized in the Aglossa. 



Rudiments of the more persistent elements of the typical annulus 

 may be recognized in this expanded formation, especially in the male. 

 The bronchial processes are plainly representented by the two lateral 

 posterior lobes, which lie upon the cardiac side of the organ, while 

 the pharyngeal point may represent the pharyngeal process. At the 

 sides anteriorly, the cartilage is discontinuous; the enormously ex- 

 panded ring muscles being stretched across the interval. The shape 

 and size of the entire apparatus shows marked sexual differences 

 (Figs. 46 — 47). The annulus of the female is in general smaller but 

 wider than that of the male. Tlie disposal of the open posterior 

 margin and its lobes and notches is also ditierent. 



9. Aglossa. 



My knowledge of these forms rests upon hasty study four years 

 ago of single male specimens of each of the two genera, and is, 

 therefore, very imperfect. It has been fortunately reinforced, however, 



