458 PROCEEDINGS OF THE ACADEMY OF [Julv, 



Fig. 26 is somewhat further from the tip of the suout and cuts 

 through the extreme point of the lower jaw, l.j. On either side 

 of the large, median, nasal cartilage, n.c, is seen the nasal canal, 

 l.n.c. and r.yi.c. On the left, the canal is, at this point, somewhat 

 circular in cross section, while on the right, which, it will l)e 

 remembered, is nearer to the base of the snout, the canal is more 

 elongated in a dorso-veutral direction. The walls of the nasal 

 passages are lined with cilia, and are, in most places, many cells 

 thick. On account of the low magnification used, no attempt has 

 been made to represent the cilia and cell outlines in these figures. 

 The collections of cells, t.r., in this and the following sections are 

 the rudiments of the teeth. At the point represented in fig. 2e, 

 the nasal cartilage, ?i.c., has increased considerably in extent and 

 almost completely surrounds the nasal passages on each side. In 

 this and the following two sections, the plate of cartilage, b. , which 

 lies ventral to the nasal passage on each side, seems no longer to 

 be continuous with the vertical septum, s., as in the preceding 

 figure, although it is still in close contact with it. The nasal 

 canals are drawn out, in this section, in a ventro-lateral direction, 

 until their passages are reduced to mere slits. The passage on the 

 right is drawn out, laterally, toward a small group of cells, r.n.g., 

 the apparent rudiment of one of the nasal glands. The teeth 

 rudiments, t.r., are seen in both upper and lower jaws, in the 

 former of which they are very large, in proportion to the size of 

 the jaw. The cartilages of the lower jaw are seen on each side, 

 m.c. 



In fig. 2d the nasal canals are still more closely invested by the 

 nasal cartilages. On the right, the section passes through the open- 

 ing of the right nasal gland, r.n.g., into the nasal passage of the 

 •corresponding side. On the left side of the section is seen the left 

 nasal gland, l.n g., cut in front of its opening into the uasal pas- 

 sage, that is, between this opening and the tip of the suout. In 

 all the following figures anterior will mean toward the tip of the 

 snout, posterior will meau toward the base of the snout or of the 

 head. 



Fig. 2e is a short distance posterior to the last figure. On the 

 right it passes through the extreme anterior edge of the right eye, 

 c, while on the left the section is anterior to the eye. The nasal 

 cartilage, n.c, on the right, completely encloses the nasal passage 



