52 DR. HARVEY ON THE ORGAN OF JACOBSON. 



actual spot where the Stenonian canal opens into this chink the 

 organ of Jacobson is still an unclosed diverticulum. The carti- 

 lage has, however, become C-shaped, and the neck of the diver- 

 ticulum constricted ; and a very little farther back the neck has 

 become obliterated, and the cartilage is a complete ring. The 

 epithelium of the tube now assumes the cylindrical form, and 

 in the connective tissue which separates it from the cartilage 

 numerous Bowman's glands are embedded. 



III. The Hedgehog. — My observations in the case of the 

 hedgehog are confined to a single specimen — an old male — ^just 

 coming out of the state of hibernation. 



The state of things found in this animal is, in the main, 

 similar to that found in the kitten. The Stenonian canals open 

 into the mouth at either side of a papilla. As we trace them 

 to the nose, we find them running a more sinuous course than 

 in the kitten. At first they pass upwards, and outwards, and 

 have a rim of cartilage on their outer sides. They then assume 

 the general direction of upwards and backwards, and in succes- 

 sive sections the cartilage is found first at the outer side, then 

 above, and lastly to the inner side. When this last stage is 

 reached the commencement of the organ of Jacobson is seen, 

 just, as in the cat, as a diverticulum, which is received into the 

 concavity of the cartilage. At the spot where the Stenonian 

 canal enters the nostril there is free lateral communication be- 

 tween Jacobson's organ and the nostril, but immediately behind 

 this point both cartilage and epithelium undergo much the same 

 modifications as described in the case of the cat. The deepening 

 of the floor of the nostril is comparatively gradual, not sudden — 

 as in the cat — and the two tubes which run side by side, with 

 very much the same direction, enter it obliquely. In the 

 cat the tubes are nearly at right angles, the organ of Jacobson 

 being nearly horizontal, and the Stenonian canal nearly vertical. 

 There is an appearance on the surface of the crest of bone into 

 which the cartilage of the n*sal septum is inserted which is 

 extremely like the commencement of the organ of Jacobson in 

 the mouse, namely, an overhanging ledge. But on tracing this 

 backwards we find it still persistent at the spot where the organ 

 enters the nostril, and, though immediately above it, still quite 

 distinct from it. 



In the present paper I have only described what may be called 

 the rough anatomical relations of the organ of Jacobson in the 

 three animals, as I think they may be of interest in connection 

 with Dr. Klein's papers. I hope subsequently to record my 

 observations, as yet incomplete, of the minute structure of the 

 nasal epithelium. 



