SKELETON AND LAETNX OP XEJSrOPUS AND PIPA. 127 



g.e. Area of insertion of the m. geniohyoideus externua. 

 gl. Position of the glottis. 

 h. Hyoglossal foramen. 



i. Isthmus between the anterior and posterior portions of the basal plate. 

 i\ Ligament in the male Pipa equivalent to the cartilaginous isthmus of the 



female. 

 I. Ligament in the male Xenopiis equivalent to the cartilage, z. fig. 1, of the 



female. 

 I'. Ligament binding the cricoid cartilage to the posterior epiphysis of the 



thyrohyal, 

 pc. Procricoid. 

 r. Eing of cartilage surrounding the aperture of the lung. 

 t. Thyrohyal. 

 V. Surface of articulation between the arytenoid rod and the roof of the 



larynx. 

 vc. Rudimentary vocal cord. 



X. Posterior limit of the basal plate of the hyobranchial skeleton. 

 y. Anterior border of the basal plate. 

 z. Bar of cartilage connecting the ala with the basal plate, 



Plate 10. 



Fig. 1. Xenopus Imvis, female. Muscles of the ventral surface of the larynx. 

 (X2|.) 



2. Xenopus lavis, female. Muscles of the dorsal surface of the larynx. 



(X2|.) 



3. Xenopus Icsvis, male. Muscles of the ventral surface of the larynx. 



(X2y 



4. Xenopus Icevis, male. Muscles of the dorsal surface of the larynx. 



(X2^) 



5. Pipa amerieana, female. Muscles of the dorsal surface of the larynx. 



( X 3g .) At the top of the figure the three divisions of the hyoglossus 

 are seen issuing through the hyoglossal foramen. 



6. Pipa amerieana, female. Muscles of the ventral surface of the larynx. 



(X3i.) 



Reference letters to Plate 10. 



a. Area of insertion of an ill-defined muscular tissue. 



b. Bronchus. 



c. M. compressor glottidis. 



d. M. dilator laryngis. 



d'. Accessory slip of the dilator muscle. 

 d.a. M. dilator laryngis anterior. 



g. Glottis. 

 g.i. M. geniohyoideus internus. 

 h.e. M. hyoglossus externus. 

 h.i. M. hyoglossus internus. 

 o.i. Laryngeal tract of the m. obliquus internus. 

 p. M. petrohyoideus. 



