64 ME. W. G. EIDEWOOD ON THE HTOBEANCHIAIi 



body of the hyoid o£ Bonibinator are exceptional, and these are 

 not represented in Xenopus ; but tbe large size of tbe lateral 

 processes of the hyobranchial skeleton, more especially the 

 posterior pair, is significant, and the great breadth of the plate- 

 like hyoidean cornua renders them remarkably similar to those 

 of Xenopus. The laryngeal skeleton of Bomlinator is not only 

 expansive and dome-shaped, and larger in the male than in the 

 female, but is also elongated in an antero-posterior direction^ 

 especially in the male sex. These features are well illustrated 

 by Wilder (42. Taf. 21. figs. 45-47), but in his figures he- 

 unfortunately omits the conspicuous bronchial processes that 

 project from the posterior edge of the cricoid cartilage (PI. 11. 

 fig. 13, &r.). Tbe broadening of the cricoid 'cartilage in Bom- 

 hinator is, as in JDiscoglossus (where, owing to the larger size of 

 the larynx, the fact can be better made out), confined to the roof 

 and floor. The sides consist of mere bands or rods of cartilage 

 extending vertically from roof to floor, and the ligament that 

 runs out to the thyrohyal epiphysis is attached to the middle of 

 the external surface of the bar. 



In the Discoglossidse, as in the Aglossa, there are no traces of 

 what Henle (p. 11) calls the cartilages of Santorini, small 

 abstricted portions of the arytenoid cartilages occurring in a 

 limited number of Anura, and first figured by Saint- Ange (36. 

 PL 26. figs. 4 & 5). They are the " pre-arytenoid " cartilages of 

 Ecker (12) and the " apical " cartilages of Wilder (42). The 

 absence of these cartilages, however, cannot be allowed to carry 

 much weight, since they are not constant in closely allied genera, 

 and may even be sometimes missing in the female of a species 

 normally possessing them (12. p. 313). 



Male. 

 The sexual diff'erences in the laryngeal skeleton, so striking in 

 the aglossal Anura, are nevertheless not confined to them. 

 Wilder (42) has already pointed out that in Bufo there are 

 suggestions of sexual dimorphism in the larynx, and that im- 

 portant sexual difierences occur in the Hylidse and in Bombinator. 

 But the increased size and complexity of the larynx in the male 

 is even more widely spread among Anura than he indicates.^ 

 Ecker (12. p. 313) has shown that in Bana esculenta the 

 arytenoid cartilages are thick, strong and large in the male, and 

 thin, smaller and more hollowed in the female. In Alytes and 



