372 
The colour is very dark violet or black, with more or less 
numerous very small lighter spots, and more or less distinet, close- 
set, fine longitudinal and transversal lines of a lighter colour, which 
may give the skin a somewhat wrinkled appearance. These lines 
appear to be more developed on the ventral side. The skin is very 
brittle, falling off in small rags, disclosing the underlying white 
Fig. 54—55. ’ Chiridoia nigra. 54. Wheel. ^°/i. 55. a. rods from 
tentacles; b. lenticular Ijodies from longitudinal muscles; 
c. ciliated funnels. a—b. ; c. ®o/i. 
muscle coat; this may give the specimens a very conspieuously 
mottled appearance, which is, however^ unnatural, the living spe¬ 
cimens being uniformly dark coloured, the small light spots men- 
tioned above being hardly discernible without a lens. In the pre- 
served specimens the wheel-papillæ form very conspieuous white 
spots, but this is due to the skin covering being lost. In a few 
cases, however, the skin covering of the papillæ is preserved, and 
also these show off as white spots; it may therefore well be con- 
cluded that in the living specimens the wheel-papillæ are visible 
as white spots. Otherwise the skin is smooth, without papillæ. 
The wheel-papillæ appear to be confined to the dorsal side, 
forming an irregular longitudinal series in each of the three dorsal 
interradii. They are generally very large, compact, somewhat oval 
in shape, and contain a very large number of wheels, lying very 
compaetly. In one such papilla I counted 165 wheels. The shape 
of the wheels (Fig. 54) is the usual, the size varying from 100 to 
140 (U. Along the radial muscles numerous small elongate-oval. 
