362 Henry L. Bruner 



Fig. 5. From Desmognathus fusca. Enlarged 22 diameters. Frontal section 

 through the turbinal prominence [T.) close behind the origin of the 

 musculus dilatator naris. 



Fig. 6. From Amblystoma tigrinum. Magnified 10 diameters. Frontal section 

 through the caudal part of the fenestra rostro-lateralis (between Co. and 

 C.I.), including the opening of the ductus naso-lacrymalis [D.nl.) into 

 the nasal cavity. In the section is shown also the intranasale [Intr.], 

 divided by the lacrymal duct into two arms, from the more median 

 of which arises the musculus dilatator naris {3Ld.n.). 



Fig. 7. Diagram to illustrate the arrangement of the nasal muscles of the Sala- 

 mandrina and their relations to the cartilaginous nasal capsule. In 

 Amblystoma, Desmognathus and Plethodon the intranasale lies in the 

 caudal part of the fenestra rostro-lateralis, just in front of the ductus 

 naso-lacrymale [D.7il.]. 



Fig. 8. Diagram of the nasal muscles of Eana fusca. The cartilago obliqua 

 terminates free behind and is bent strongly forward at its ventral 

 end, so that a line from the external nasal opening to the anterior 

 angle of the planum terminale becomes almost vertical. Such a line 

 represents approximately the axis of the plica obliqua, which in Rana 

 contains at its lower end the musculus dilatator naris {3I.d.n.], and 

 above connective tissue [Ct.). Directly in front of the planum termi- 

 nale lies the lateral arm of the intranasale, beneath which the ductus 

 naso-lacrymalis opens into the nasal cavity. The caudal part of the 

 cartilago alaris [Ca.], which naturally strikes against the plica obliqua, 

 has been removed. 



Fig. 9. From Rana fusca. Magnified 12 diameters. Longitudinal vertical 

 section through the apertura naris externa. The section passes 

 through the plica obliqua [Pl.o.), and includes that portion of the 

 musculus dilatator naris [M.d.n.) which arises from the lamina in- 

 ferior [L.i.). In the upper lip is shown the musculus labialis superior. 



Fig. 10. From Rana pipiens. Magnified 10 diameters. Oblique frontal section 

 through the nasal region, to illustrate the arrangement of certain 

 parts of the mechanism for opening and closing the external nares; 

 supplementary to Fig. 13. In the section the lower jaw lies in place 

 in the sulcus marginalis. The plane of the section passes through 

 the fossa subrostralis media, the facial processes of the two inter- 

 maxillaria [Int.fac), and the tuberculum praelinguale. The last is 

 formed by the two exposed ends of Meckel's cartilage [Mck.), which 

 are united in the middle line by a loose syndesmosis [S.]. A similar 

 syndesmosis exists in the middle line between the palatine portions 

 of the two intermaxillaria, and also on each side between the pars 

 dentale of the intermaxillare and the maxillare (indicated also by S.). 

 The figure shows the relation of the processus praenasales superiores 

 to the facial processes of the intermaxillaria. 



Fig. 11, From Rana esculenta. Magnified 12 diameters. Frontal section through 

 the apertura naris externa and the upper portion of the plica obliqua 

 [Pl.o.), to show the relations of the anterior part of the musculus 

 constrictor naris {M.c.n.). The principal part of the muscle lies in the 

 median margin of the nasal opening, but below this part small bundles 



