66 ME. W. Q. EIDEWOOD ON THE HTOBEANCHIAL 



larynx of the male is complete *, tlie membranous spaces whicli 

 occur between the anterior ends of the thyrohyals in the female 

 being filled up by cartilage. The portion of the side-wall of 

 the larynx situated externally to the arytenoids is much more 

 massive in the male; and, whereas in the female the blinker- 

 shaped process terminates anteriorly in an abrupt edge, it fuses 

 in the male with the true basal plate of the hyobranchial skeleton 

 (PI. 8. fig. 6, bl.). The cricoid cartilage is very much thicker 

 than in the female, and the thickening has proceeded irregularly 

 into the interior of the larynx (PI. 8. fig. 5) in a manner recalling 

 the formation of the turbinal ingrowths of the nasal capsule in 

 higher vertebrates. The general impression is one of solidity 

 and massiveness, in striking contrast with the delicacy and 

 elegance of the female larynx. 



A comparison of median sections of the male and. female 

 larynx (PI, 8. figs. 5 and 2) shows that most of the differences 

 are those of degree and not of kind ; but there is one most 

 important structural dissimilarity to be noted. The posterior 

 processes of the arytenoid cartilages of the male are confluent 

 with one another (PI. 8. fig. 6, ar.'). The union is brought 

 about by a thin horizontal sheet of cartilage, situated immedi- 

 ately behind the glottis, and dorsal to the broad, flat, articular 

 surfaces by which, as in the female, the two massive parts are 

 applied to one another in the median plane (see fig. 5). The 

 relations of the connecting cartilage are such as to warrant the 

 assumption that there is here a procricbid cartilage, not free as 

 in the female Pipa (PI. 9. figs. 2 and 3, pc), but united on either 

 side with the arytenoids. This is certainly the most plausible 

 explanation o£ the facts, but it involves the curious anomaly, 

 that a procricoid cartilage is present in the male Xenopus and in 

 the female Pipa, while no trace of it can be detected in the 

 female Xenopus and in the male Pipa. The arytenoids proper 

 (PL 8. figs. 5 and 6, ar.) stand nearly vertically, and do not 

 slope downwards and outwards as in the female. Henle (p. 18) 

 states that the arytenoids are ossified in the male, but this I am 

 not in a position to confirm. 



The bronchial cartilages are disposed just as in the female. 

 The bronchi have long been known to be shorter in the male 

 than in the female, but undue stress seems to have been laid on 

 this fact in consequence of the failure to take into account the 



* Wilder erroneously states it to be entirely membranous (42- p. 292, and 

 Taf. 21. fig. 59). 



