340 Henry L. Brunei- 



general process of folding which has affected the structure of the 

 entire nasal region in Anura. Later, Gaupp (19) rejected Born's 

 homology as applied to the Anura, on the ground that in Rana the 

 bone in question is so far removed from the orbit. Accordingly 

 Gaupp discarded Born's name lacrymale and substituted for it the 

 term intranasale. From my own study of Plethodon, Desmognathus 

 and Amblystoma, in which both a lacrymale of Born and the septo- 

 maxillare of Parker are present, I am led to adopt Parker's 

 homology as correct. I have used, however, here, as I have pre- 

 viously done for the salamanders, the name intranasale as proposed 

 by Gaui^p. 



b. Description of new Nasal Muscles. 



The description given above shows us, in the nasal region of 

 Rana fusca, a number of structures which we have already found 

 in Triton. For example, we find in both species a cartilago obliqua 

 with its planum terminale, a turbinate prominence formed by the 

 incurving of the planum terminale into the nasal cavity, and a glandula 

 nasalis externa. But other structural resemblances may also be 

 discovered. In the description of the nasal region of Rana fusca a 

 fold (plica obliqua) was mentioned which demands, first of all, our 

 attention. This fold begins as a low thickening at the anterior end 

 of the turbinal or more definitely, on the prominence which is formed 

 by the incurved anterior angle of the planum terminale and the 

 lateral arm of the intranasale (see Fig. 14). From this point the plica 

 obliqua extends in a dorsal direction toward the nasal opening, 

 becoming meanwhile more elevated, and inserts finally on the medial 

 margin of the nasal opening, through which its dorsal end can be 

 easily seen with the aid of a pocket lens. 



From the above it will be seen that the plica obliqua occupies 

 a position strikingly similar to that of the nasal muscle thickening 

 of Triton. But if the two structures are genetically related, we 

 should expect to find in the plica obliqua, if anywhere, traces of 

 the nasal muscles of Triton. My investigation of the plica and the 

 adjacent region has led to the following results: 



In the ventral (caudal) part of the plica obliqua lies a small 

 smooth muscle whose bundles arise i)artly from the incurved margin 

 of the planum terminale, in part also from the adjoining medial 

 end of the lateral arm of the intranasale and from the lamina inferior. 

 From this point of origin the muscle extends toward the nasal 



