The Smooth Facial Muscles of Anura and Salamandriua. 363 



of fibers (/.) insert under the epithelium of the lateral surface of the 

 plica obliqua [Flo.]. Isolated bundles of smooth muscle fibers radiate 

 from the wall of the vestibule of the cavum superius [V.c.s.\ as indi- 

 cated by the letter h. In the upper lip the musculus labialis superior 

 tM.l.s.' is shown. 



Fig. J 2. From Rana fusca. Magnified 12 diameters. Frontal section through 

 the mm. constrictor naris and dilatator naris. The former is cut 

 through its posterior half and shows below the scattering bundles 

 which arise about the glandula nasalis externa. The dilatator naris 

 is cut longitudinally, but not directly through the axis, so that the 

 upper part of the plica obliqua is not contained in the section. The 

 musculus labialis superior shows as in Fig. 11. 



Fig. 13. From Rana fusca. Magnified 20 diameters. Horizontal section through 

 the cartilago alaris {C.a.) and the dorsal end of the plica obliqua 

 [FLo.]. The relations which provide for the impact of the cartilago 

 alaris against the plica obliqua during the closing of the external 

 naris are clearly shown. The weak ventral part of the musculus 

 constrictor naris [M.c.n.) is included in the section. 



Fig. 14. From Rana fusca. Magnified 20 diameters. Horizontal section passing 

 through the ventral parts of the plica obliqua {Fl.o.), and showing the 

 relations of the dilatator naris [M.d.n.] to the intranasale [Tntr.] and 

 to the incurved margin of the planum terminale [F.t.]. The ductus 

 naso-lacrymalis [D.nl.) passes forward beneath the glandula nasalis 

 externa [Gl.n.e.) and the caudal arm of the intranasale, and opens into 

 the cavum medium (not shown in section). 



Fig. 15. From Bombinator igneus. Magnified 12 diameters. Frontal section 

 behind the external naris, to show the relations of the intranasale, 

 a process of which lies in the plica obliqua [Fl.o.]. The musculus 

 labialis superior is seen in the upper lip. 



Morpholog. Jahrbuch. 2y. ' 25 



