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almost lying in the same plane as the other chitine, 
and that the inside of the cave is not smooth (as by 
those of the hairs of Araneæ described by Wagner), 
but the bottom and the sides are covered with a thinner, 
most remarkable stratum of chitine-formations. These 
appear to be lamellæ, projecting almost vertically and 
coalesced to form a more or less irregular, sixangular 
cavity, giving vou the impression, that the cave is 
covered with a stratum of prismatic »cells«, very much 
reminding of the cells in a honeycomb. Ishall, however, 
leave to others the more minute histological study of 
these beautiful formations. 
C. Other Sense-Organs. 
Nothing but the eves and crests is known; relative 
to the latter ones I refer to the work of Gaubert. I 
shall, however, call attention to a new organ, that 
undoubtedly must be a sense-organ. An oval, slightly 
convex spot is seen in Pandinus cyaneus C. Koch on 
the. upper side of the last joint of all 4 pairs of legs 
close to and slightly behind the basis of the median 
process. If this spot besides some of the surrounding 
integument is cut off and examined with the light falling 
through, a shape is seen almost like Tab. II, fig. 4. It 
is seen that the area of a clear greyish tone, given in 
the figure, is much richer provided with pore-channels 
(a) than the surrounding integument, and that these 
channels, of which but a few are indicated in their 
whole extension, converge towards the centre of the 
area. Moreover there are in the area 9 rather large 
cavities (b), converging likewise towards the centre, 
shaped like a truncated cone with a large interior aper- 
ture and ending externally in a much smaller area, 
much larger, nevertheless, than an ordinary pore-channel. 
This small area is covered by a thin membrane, from 
