54 ME. W. G. EIDEWOOD ON THE HTOBEAKCHIAL 



study of the latter is necessarily demanded ; and, in order to 

 insure the correctness of the morphological value attributed to 

 the various parts, a chapter on the development of the hyo- 

 branchial skeleton is added. I have studiously avoided all refer- 

 ence to the columella auris and stapedial cartilages, since these 

 are not related anatomically with the larynx. The expression 

 " hyobranchial skeleton," therefore, is here used in a limited and 

 strained sense ; but I do not think that any confusion is likely 

 to be caused by this departure from the strict application of the 

 words. 



Passing over the works of Fermin (13) and Schneider (37)^ 

 who mention only incidentally the hyobranchial and laryngeal 

 skeleton of I*ijpa — Xenopus was not then known, — the first de- 

 scription of these parts occurs in a short monograph by Breyer 

 on Fipa (4. 1811). Mayer (25) in his treatise on the same 

 animal, published fourteen years later, describes for the first time 

 the muscular system. He furnishes a detailed account of the 

 larynx of both sexes; but the description suffers considerably 

 from the lack of pictorial illustration. In his second contribution 

 (26. 1835) he describes the muscles of the hyoid apparatus of 

 Xenopus, and treats of the laryngeal skeleton of botb sexes. To 

 bis figures of the Xenopus larynx (Taf. 3. figs. 6 & 7) he adds, 

 for purposes of comparison, one of the larynx of the male Pipa 

 (Taf. 3. fig. 5). By far the greater part of our present know- 

 ledge of the subject we owe to the patient and exhaustive investi- 

 gations of Henle (19). Although bis book refers to the vertebrate 

 larynx generally, he has devoted quite an exceptional amount of 

 space to the aglossal toads, and has allotted to them the whole 

 of one of the five plates by which his work is so admirably 

 illustrated. He describes with great care the hyobranchial 

 skeleton of Xenopus and Pipa, the laryngeal skeleton of both 

 sexes, and the laryngeal muscular system of the female Pipa and 

 the male Xenopus. Henle was the first to suggest (p. 15) that 

 the hyoglossal foramen, so characteristic of the Aglossa, is formed 

 by a union of the anterior or hyoidean cornua, and that the hind 

 edge of the foramen corresponds with the notch at the front of 

 the body of the hyoid in other Anura. He agrees (p. 16) with 

 Meckel (27. p. 229) and Mayer (26. p. 31), that the anterior 

 cornua have been reduced in Pipa and are only represented by 

 the delicate pointed cartilage at the front of the hyobranchial 

 apparatus. Henle also (p. 16) propounded the view, already 

 hinted at by Mayer (25. p. 541, and 26. p. 31), that the anterior 



