60 MR. "W. Q. EIDEWOOD ON THE HTOBEANCHIAL 



and of tlie development of the rods themselves, to firmly establish 

 the homology. The posterior ends of the thyrohyals are wider 

 apart than the inner edges of the alae, and lie below or ventral to 

 the latter. The posterior epiphysial cartilages are bound by a 

 very short and tough ligament to the ventral surface of the alae, 

 just external and slightly posterior to the notch on their inner 

 edge already mentioned. 



Laetngeal Skeleton oe Xenopus Icevis. 

 The first account of the larynx of Xenopus is that of Mayer 

 (26. 1835). He describes both sexes and gives figures of each 

 (Taf. 3. figs. 6 and 7). Henle (19), like Mayer, discusses both 

 sexes, and his figures of the dorsal and ventral surfaces of the 

 female larynx (Taf. 2. figs. 1 and 2) are exceedingly accurate. 

 The larynx described by "Wilder (41. p. 573, and 42. pp. 291 and 

 292) must have been in a sad state indeed if his figures (42. Taf. 21. 

 figs. 58-61) represent it at all truthfully. These show a number of 

 dismembered cartilages in the roof, and no cartilage in the floor. 

 It is, also, hardly just and fair to condemn Henie's excellent work 

 and to charge him with overlooking the true arytenoids, on the 

 strength of observations made, as Wilder himself admits (42. 

 p. 290), on a single specimen. This most recent contribution of 

 Wilder's is so good in the main that it is a great pity it has been 

 marred by the incorporation of the results of " hasty study." 



Female. 

 The larynx proper of Xenopus differs from that of the more 

 normal anuran, not only in its superior size and the extensive 

 spreading of the cricoid cartilage so as to form an almost com- 

 plete laryngeal bos, but more especially in the union of the 

 lateral edges of its floor with the inner surfaces of the ossified 

 thyrohyals, the confluence of the anterior region of the floor 

 with the back of the basal plate of the hyoid, and in the coa- 

 lescence which has taken place between the posterior epiphysis of 

 the thyrohyal and the postero-lateral corners of the cricoid. 

 Although the lateral edges of the floor of the larynx are so 

 closely applied to the columellae, the actual sides of the larynx 

 are free, and the narrow space between them and the thyrohyals 

 is filled with a fatty tissue similar to that found on the under 

 surface of various parts of the hyobranchial skeleton. There is 

 a pear-shaped membranous area (PI. 8. fig. 2,/) in the cartila- 



