398 THE NASAL REGION IN EUTAENIA. 



(2) The capillary plexus, which is directly continuous with that 

 mentioned above ; the rest of the mucosa is occupied by 



(3) The abundant pigment cells which spread out at the junction 

 of floor and roof to surround the cellular columns in the mode de- 

 scribed above." 



Prof. Wright's and my own studies further on the same subject 

 have 'given the folio wins; : 



The sensory stratum is divided into (1) the cellular columns 

 already mentioned, oblong in section in the body of the organ, but at 

 its posterior termination, polygonal, completely surrounded by the 

 constricting plexus at all but one point, where their cells pass 

 gradually over into those of (2) the sensory portion adjacent to the 

 superficial stratum, and consisting of two or three layers. The 

 cells of the second portion of this stratum do not exhibit any differ- 

 ence from the sensory cells of the nasal passage, except that the 

 nucleus in each and the portion of the cell containing it are more or 

 less fusiform. In those of the columns, however, the central and 

 peripheral processes are undistinguishable, so far as shape is con- 

 cerned, both exceedingly delicate and wavy in their course. When 

 the columns, macerated in Muller's Fluid, are teased out, minute 

 portions will be frequently seen through which the delicate processes 

 pass in every direction. The nucleus in each is large, distinct and 

 quite spherical, with little protoplasm surrounding it. Through the 

 point of the connection of the columns with the rest of the sensory 

 cells, their peripheral processes reach down between the latter to 

 the lumen of the organ and terminate like them. 



The terminations of the sensory cells in the lumen are knob-like 

 and about one-fourth the length of the sense-hairs in the nasal pas- 

 sage. With such a length all capability of movement is absent- 

 There is no swelling to be observed at the base of each. 



In the superficial stratum the cells have the same shape as in the 

 nasal cavity. They are provided with the same distinct border 

 structure, through which the sensory terminations push. Of any 

 prolongation of the protoplasm of the superficial cells beyond this 

 border structure no convincing proof has been met with as yet. In 

 several cases a faint striation parallel with the cylindrical cell was 

 observed at its border. This was replaced by a delicate granular 

 precipitate in macerated specimens. The number of cases in which 

 such a striation was observed, were few in comparison to the amount 

 of material examined. It is, however, quite probable that the cylin- 

 drical cells are provided with cilia as excessively fine as these of the 

 nasal cavity. 



The border structure must be regarded as the homologue of the 

 membrana limltans olfactoria of the nasal cavity. 



