Bawden, Nose and Jacobsons Organ. 133 



tadpoles (od, Fig. 5, Plate X; also Fig. 5, Plate XI.) A close 

 homology will be seen to exist between this type and other 

 Urodela. See Figs. 3, 4, nl, or, op, ey, etc., Plate XII. 



A very similar condition and relative position for this duct 

 is seen to exist in Amblystoma punctatum. Its entire course from 

 the point where it originates upon the lateral aspect of the cav- 

 ity from its peculiar diverticle (see or, Figs. 3 and 4, Plate XII) 

 to its opening upon the lower lid of the eye {op, Fig. 3, Plate 

 XII ) is seen in Fig. 3, Plate XII. Its course, as in Salamandra 

 atra, is in general parallel to the longitudinal axis of the nasal 

 cavity. Having its origin just behind and a little mesad of the 

 exterior nares it courses backward, ending just dorsad and a lit- 

 tle laterad of the internal nares. 



Fig. 3, Plate VI is a transverse section showing the origin 

 of the naso-lachrymal, ;//, from the general cavity of the nose, gen. 

 In this figure is seen the opening of the cartilaginous investment 

 through which this duct makes its exit between the two internal 

 processes, in. The real tube of this duct can only be distin- 

 guished from the many gland ducts with which it is associated 

 by this internal connection with the general cavity, gen. The 

 structure of this duct, and the epithelium membrane which lines 

 it is nicely shown in Fig. 5, Plate VI where it is revealed under 

 a high power. In Amblystoma this duct appears at one point 

 to be completely enclosed within the bony investment, but for 

 only a short distance. See Fig. 5, Plate VI, #and mx. Ey, Figs. 

 3 and 4, Plate XII, as in S. atra, shows the eye much reduced, to 

 illustrate the method of termination of the duct. 



In adult Anura, Hyla versicolor, Bnfo lentigenostis, 

 Rana virescens etc. , the outer tip of the lateral cul-de-sac breaks 

 through the investment (see Figs. 3 and 4, Plate VIII, nl and 

 of) and makes its way through the bony environment in the 

 form of a tube extending outward and backward toward the eye 

 (nl, fig. 5, Plate VIII). In Pelobatesfuscus, says Born (No. 4), 

 the canal passes backward, as mentioned, only in this case en- 

 closed in a tubular extention of the bone. In other Anura it 

 lies in a mere hollow in the bone. From this point, as in the 

 other cases, it passes in the direction of the under eyelid where 



