The Smooth Facial Muscles of Anura and Salamandrina. 351 



the nasal opening. 3) On each side, a m. narium, which arises from 

 the facial process of the maxillare and inserts on the inferior nasal 

 cartilage. These muscles were supposed to open the nares. 



DuGES (15) accepted the results of Zenker's work in 1835 and 

 designated the muscles as follows: 1) intermaxillaire, 2) sus-maxillo- 

 pre-nasal, 3) sus-maxillo-post-nasal. In opposition to Zenker, however, 

 DuGES held that the second muscle was also a dilatator. The closing 

 of the external nares he accounted for by the contraction of the 

 submentalis muscle. 



Klein (29) described again (1850) the same muscles under the 

 names: 1) intermaxillaris, 2) nasalis inferior, 3) nasalis externus. 



Ecker (16) adopted (1887) the two first muscles of Duges and 

 Klein, but declared that he could find no evidence of the existence 

 of the third muscle. 



If now we examine critically the above descriptions, we shall 

 find no resemblance, either of position or attachment, between the 

 muscles described by Zenker and his followers and those which I 

 have described in Rana. Of the muscles described by the earlier 

 authors, numbers three (m. narium Zenker) is the only one located 

 near the muscles which I have described in Rana. But the m. 

 narium, as described by Zenker, should lie much farther lateral 

 than the m. constrictor naris, while its position differs entirely from 

 that of the m. dilatator naris. We cannot, therefore, establish 

 a case of homology between the two groups of muscles. 

 This conclusion agrees with the observations of those investigators, 

 who have called in question the existence of the muscles described 

 by Zenker. We find, for example (1838), in Volkmann (50) the fol- 

 lowing expression in regard to the muscles described by his pre- 

 decessors, Zenker and Duges: 



»Nasenmuskeln. Über diese bin ich im Unklaren geblieben, in 

 80 fern die Theile, welche, mit bloßem Auge betrachtet, für Muskeln 

 gehalten werden müssen, unter dem Mikroskop einen zweifelhaften 

 Bau zeigen. Bis auf weitere Berichtigung können zwei angenommen 

 werden: 23) Depressor alae nasi scheint vom Körper des Zwischen- 

 kiefers zu entspringen und am vorderen, knorpeligen Rande des 

 Nasenloches zu endigen. 24) Depressor alae nasi externus scheint 

 vom Oberkiefer zu entspringen und gleich dem vorigen zu endigen.« 



A later paper by Volkmann upon this subject I have not been 

 able to find. His doubt in regard to the existence of the muscles 

 in question found acceptance with Heinemann (24), who supports 



