Bawden, Nose and Jacobson's Organ. 145 



5, Plate X, and Fig. 6, Plate XI, revealing the entrance of the 

 olfactory nerve-bundles from the olfactory tuber, oln. This view 

 corresponds to a section of the model taken at D, Fig. 5, Plate 

 X. In this section the opening in the cartilaginous fossa, in, 

 shows the bundles in their connections with the bulb. Fig. 2, 

 Plate X, is a section taken more ventrad, represented on the 

 model as a section at E, Fig. 5, Plate X. This horizontal sec- 

 tion shows the opening from the general nasal cavity, gen, into 

 the outer smaller diverticle od, also the external nares extl, and 

 the upper wall and very small beginning of the lumen of the 

 cavity of the larger inner diverticle, id. In Fig. 3, Plate X, 

 represented by a section of the model taken at B, Fig. 5, Plate 

 X, we see the opening of the general cavity gen, into that of 

 the inner diverticle, id. Also we see the great thickening of 

 the inner wall, t, in the vicinity of the internal nares. It seems 

 to be constant throughout that the wall becomes thickened on 

 the inner, median side probably due the fact that it is on this side 

 that the nerve termini make their closest connections. It is 

 also on this inner aspect of the nasal cavity that corrugations 

 generally appear, due perhaps to the entering, at different 

 points, of distinct nerve-bundles. Fig. 4, Plate X, shows the 

 internal nares, intl, and is represented by a section of the model 

 in the plane indicated at C, Fig. 5, Plate X. Here again we 

 notice the thickened inner epithielium wall, /. In Fig. 1, Plate 

 VIII, we have a horizontal section of another specimen than the one 

 modelled, from which the previous drawings were taken. This 

 tadpole was also somewhat younger, but sufficiently similar to 

 make comparisons with the same model. Here is seen the 

 outer diverticle in a slightly different plane upon each side of 

 the head, od, and also the external nostril, extl, upon the right 

 side. A section taken at A, Fig, 5, Plate X, would show such 

 a view as this. Fig. 2, Plate VIII, is a drawing of a transverse 

 section also of a younger specimen, showing the opening into 

 the lumen of the outer diverticle, od, and also showing a nerve- 

 bundle entering upon its median-dorsal aspect, oln. Such a 

 view would appear in a section of the model taken in the plane 

 indicated at F, Fig. 5, Plate X. 



