WILSON ON THE NERVOUS SYSTEM OF THE ASTERID.E. 123 
Fig. 4. Individual cones, a. bird's-eye view ; b. profile; c. lens imbedded in the base; d. nerve entering 
the apex. 
Fig. 5. Bird's-eye view of individual eyes, with a clear central space. 
Fig. 6. Oblique view of optic bulb and tactile organ, a. nerve-cord; b. optic bulb, showing very di- 
stinctly the great number of individual eyes and their arrangement, as well as the clear eye- 
less portion (c), bounded by the distal rows of cones ; d. tactile organ, very large and with 
7 
its cavity well marked : the latter may be traced passing onwards behind the bulb. 
or connected with it. a a. interambulacral cords; b> ambulacral cord; d. filaments passing 
diagonally across to the space between the arms. 
brid 
whorl of spines (b) 9 underneath which the tactile organ (c) passes to communicate with the 
water-canal (d). 
Reproduction of a lost Ray. 
Fig. 9. Ambulacral aspect of an amputated ray, at the stage in which the newly reproduced arm is just 
appearing, a. ganglion of the old ray; b b. interambulacral cords of the same; c. dorsal in- 
tegument, which has curved inwards from behind, in the form of a flap, and united with the 
skin and other structures of the ambulacral groove. 
Fig. 10. Longitudinal section of a ray, illustrating the first stage towards reproduction: the dotted part 
in the engraving is the ambulacral nerve-cord and ganglion; that shaded with horizontal lines 
represents the water-canal, #. dorsal integument* curving towards the ambulacral groove in 
the form of a flap; b. caecal cavity or chamber. 
Fig. 11. Second stage. Union has taken place between the dorsal flap (a) and the ambulacral integu- 
ment. The c£ecal chamber is continued as a cut de sac between the surfaces of the vertebral 
plates and the dorsal flap. 
Fig. 12. Third stage. The nerve-cord has sent a prolongation outwards, which is seen resting upon a 
cutaneous part formed, simultaneously with it, from the dorsal flap. Pigment is deposited at 
the terminal point of the prolongation ; and the water-canal is continued below it. 
Fig. 13. Represents the third stage still more advanced. The pigment-deposit is now seen to contain 
cones with bright specks at their bases. 
Fig. 14. Illustrates the last stage. The vertebral arches and the suckers now make their appearance. It 
will be seen, however, that the vertebrae do not continue regularly up as far as the old ones. 
The two are separated by the ligamentous structure marked x. 
Note. Figures 1* 2, 5 & 7 are copied from my Thesis. 
r2 
