564 DE, E. KLEIN. 
the muscular fibres of the heart much closer than ordinary non- 
striped muscular cells. Whena bundle of the muscular fibres of 
the cavernous layer is viewed in cross section the individual small 
elements appear in their size and structure very much like 
the muscular fibres of the heart. 
In the matrix of the cavernous tissue may be met with small 
and large bundles of nerve fibres chiefly following a longitudinal 
course; in most cases the nerve fibres are medullated fibres, but 
there are here and there bundles to be seen, the greater majority 
of whose nerve fibres are non-medullated. 
The outer boundary of the cavernous layer and the outer in- 
sertion of its muscular bundles is formed by fibrous tissue 
intimately connected with the perichondrium of Jacobson’s 
cartilage. 
(e) As regards the glands occupying the upper wall, z.e. those 
opening in the upper sulcus, as well as the glands in the lower wall, 
z.e. those opening into the lower sulcus, their structure, position, 
and change in amount has been mentioned above, and is easily 
understood from an inspection of the figures. The epithelium of 
the ducts of both groups at their mouth forms one continuity with 
the epithelium of the lateral wall, but is quite distinct from the 
sensory epithelium; the same relation has been pointed out in 
connection with the guinea-pig’s organ, where it was shown that 
these ducts form in reality the boundary between the epithelium 
of the lateral wall and the sensory epithelium, lining the median 
surface of the lumen. So it is also in the rabbit; the two epi- 
thelial structures, 7.¢. the epithelium of the lateral wall and the 
sensory epithelium being well marked of from one another, and 
the mouth of the ducts of the serous glands, both at the upper 
and lower sculcus form the boundary between them. 
2. The median wall. 
The sensory epithelium consists, like that of the guinea-pig, 
of two distinct strata—a superficial one composed of thin conical 
spindle-shaped or cylindrical epzthelial cells, each with an oval 
nucleus. 
The cells forming this stratum vary from one another in this 
respect, that the nucleus does not lie in all cells at the same level, 
but is placed at different depths, so that, taking this stratum as 
a whole, it appears to contain several layers of nuclei; generally 
there are between three and five such layers. ‘The nuclei are 
oval, some more elliptical than others; they stain always readily 
in dyes, and hence they are very conspicuous in specimens so 
stained. 
The part of the epithelial cell between the nucleus and the 
inner or free surface varies between 0°012 and 0:016 mm., and 
it appears clear and longitudinally striated. On the free surface 
