346 A. Ärnbäck Christie-Linde 



In front of the opening of the naso-palatine canal the upper 

 end of the cartilago paraseptalis becomes broader and its lower end 

 being connected with 'the inner part of the cavtilago ductus naso- 

 palatini Supports the duct-like foremost part of the organ of Jacob- 

 son on the inner side (Fig. 2 — 3). 



If we follow the outer part of the latter cartilage backwards, 

 we find immediately behind the naso-palatine canal a thin carti- 

 laginous striüg stretchiug backwards, widening into a thin hori- 

 zontal plate similar to that in Sorex, which plate forms for a very 

 short distance a highly rudimeutary floor of the nasal cavity, It 

 passes close under the cartilago paraseptalis; it does not unite with 



Fi- 1. Fiar. 2. 



Crocidura russula. Foetus (12'/.. ram). Transverse sections of region of Jacobson'» organ. c.ps. carti- 

 lago paraseptalis; n.p.Q, naso-palatine canal; n.s. nasal septnm; o.s.c. outer part of sickle-shaped 

 cartilage; pmx. premaxillary ; s.c. sickle-sliaped cartilage. X c. 66. 



its fellow of the other side and, just as in Sorex, disappears imme- 

 diately before the plane, where the maxillary bones appear. It is 

 this cartilage that I have called the cartilago palatina, and which 

 thus is present in a rudimentary State also in Crocidura. 



In the plane where the foremost duct-like part of Jacobsons 

 organ is observable an outward and downward process passes from 

 the upper end of the cartilago paraseptalis, and a little farther back 

 still this process is apparently free forming, in the words of Broom, 

 »for a short distance a detached bar which on section is apparently 

 neither attached to upper or lower borders«. (Fig. 2—3.) This car- 

 tilaginous bar lying on the outer side of the organ of Jacobson, 

 appears isolated orily in a few sections and soon proves to be con- 

 nected with the lower end of the cartilago paraseptalis, which now 



