458 DE. W. G. EIDEWOOD ON THE HYOBRANCHIAL 



The ring of cartilage is produced into a blunt point in front, 

 while from the sides there rise vertically upwards, internal to the 

 thyrohyal bones, but quite free from them, a pair of cartilaginous 

 bars, which end at the sides of the arytenoid cartilages on the 

 upper surface of the larynx (fig. 4, U). The dorsal extremities 

 of these cartilages appear to be the equivalents of the " Scheu- 

 klappenartige Fortsatze " described by Henle (3) in the female 

 Xenopus. 



As seen from above, the larynx bears a striking resemblance 

 to that of the young Pipa (see 4. pi. 11. fig. 11). The dorsal 

 part of the cricoid cartilage has the form of an arched band, 

 running transversely between the posterior epiphyses of the thyro- 

 hyals, and fused with them at its extremities. The arytenoids 

 are simple, concavo-convex cartilages, constructed upon the type 

 normal for the Phaneroglossal Anura. They each exhibit a small 

 centre of ossification at the point where the tendinous extremity 

 of the laryngeal dilator is inserted. 



There are no vocal cords in either sex, neither are there 

 bronchial tubes. The wall of the luug is quite smooth, and 

 exhibits no sacculation. It is as strongly vascular in the parts 

 connected with the larynx as over the general surface ; and it is 

 worthy of notice that the bronchial cartilages of HymenocTiirus 

 are not more extensively developed than in such a phanero- 

 glossal form as Bomhinator (see 4. pi. 11. fig. 13, hr). As in Pipa 

 and Xenopus, the lung is bound to the abdominal wall by a 

 stout pleural fold, which does not quite reach to the posterior 

 extremity. 



In the male, the floor or ventral wall of the larynx is composed 

 entirely of cartilage, but the cartilaginous lamellae projecting 

 from the inner borders of the thyrohyal bones (fig. 1, t') are not 

 confluent with the median cricoid. The latter terminates 

 anteriorly in a sharp point, concealed iu a ventral view by the 

 meeting of the thyrohyal lamellae just mentioned. The vertical 

 bars of the cricoid cartilage, which in the female lie internal to 

 the thyrohyal bones, are also present in the male, and are similarly 

 placed ; but they can only be seen by cutting open the larynx* 

 Their dorsal extremities are not free, but are fused with the 

 roofing part of the cricoid cartilage. The cricoid cartilage 

 extends much farther forward on the upper surface of the larynx 

 than it does in the female. It conceals the anterior part of the 

 thyrohyals, and is confluent in front with the tract of cartilage 



