The Smooth Facial Muscles of Anura and Salamandrina. 349 



and that Gaupp's attention was directed solely to the question 

 whether such muscles 1 exist. Allowing full value, then, to the excel- 

 lent work of Gaupp, and taking into consideration the imperfection 

 of earlier microscopical methods, the question may be asked, whether 

 the smooth nasal muscles which I have described in Kana might 

 have furnished a certain basis of fact for the descriptions of the 

 earlier authors. Before attempting to solve this problem, however, 

 I wish to consider the other question, whether the smooth nasal 

 muscles of Rana are homologous with those of Triton. 



a. The nasal muscles of Rana and Triton. 



From a comparison of the nasal muscles of Triton with those 

 of Rana we must expect to find no close functional similarity be- 

 tween the two groups. If homologues of the nasal muscles of Sala- 

 mandrina occur in Anura, they must have undergone a radical change 

 of function and their homology must be established therefore upon 

 purely anatomical evidence. If then we consider the dilatator naris 

 of Rana from this standpoint we find, first of all, that its origin is 

 very similar to that of the dilatator naris of Triton. The point of 

 origin is, in each case, the anterior end of the incurved portion of the 

 planum terminale (turbinal of Born and Wiedersheim). Outside of 

 the turbinal prominence the ductus naso-lacrymalis extends forward 

 and opens lateral (rostral) from the muscle into the nasal cavity. 

 The relation between the dilatator naris and the intranasale of Rana 

 does not find its parallel in Triton, in which the intranasale is 

 wanting. We have seen however that a similar relation occurs in 

 other Salamandrina (Amblystoma), where the dilatator naris is like- 

 wise attached to the inner surface of the intranasale. In respect to 

 origin, then, the dilatator naris of Rana resembles to a remarkable 

 degree the dilatator naris of the Salamandrina. General agreement 

 exists also in regard to the direction of the two muscles toward the 



1 Gaupp (20) made diligent search for such muscles. He says (Anatom. 

 Anzeiger. Bd. XII. 1896. page 25): »Ich habe weder an Spiritus- noch an 

 Chromsäure- noch an Salpetersäurepräparaten jemals Muskelfasern an den be- 

 zeichneten Stellen auffinden können. Gerade die so eben angegebenen Behand- 

 lungen lassen aber im Allgemeinen die Muskelfasern sehr deutlich erkennen, 

 und namentlich geben alte Spiritusmuskeln ausgezeichnete mikroskopische Bil- 

 der der Querstreifung. Niemals ist es mir möglich gewesen, auf diese Weise 

 in der Umgebung der Nase des Frosches Muskeln nachzuweisen.« 



24* 



