ON COLOURING MATTERS OF VARIOUS ANIMALS. 11 
dredged at Cape York. It. was not obtained in so intense 
a solution as from the Antedon, the coagulation of the gela¬ 
tinous matter in alcohol no doubt preventing so free a solu¬ 
tion. The spectra yielded by the colouring matter are 
figured (PI. II, fig. 9, a, b, c, cl, e). In some unimportant re¬ 
spects a difference between tlie colouring matter of this 
Holothurian and that from the Antedon was observed. 
The alcoholic solution of the Holothurian colouring matter 
absorbs the red and violet ends of the spectrum more than 
that of the Antedon (PI. II, fig. 9 [b), and when acidified with 
hydrochloric acid in strong solution shows a greater exten¬ 
sion of its less refrangible band towards I) than does the 
similar solution from Antedon (PI. II, fig. 9 cl). In weak 
solutions, however, it gives two bands (PI. II, fig. 9 c) coin¬ 
cident with those of the Antedon. It is probable that the 
slight difference observed is only due to the turbidity of the 
solution of colouring matter from the Holothurian, which is 
caused by the gelatinous nature of the animal. Specimens of 
the same species of Holothurian, or very similar forms, were 
several times dredged by the Challenger in deep water in 
various parts of the world, and they were found to be similarly 
coloured. 
Worms. 
Land planar tans .—At Parramatta, near Sydney, New South 
Wales, two large species of Eynchodemus arc tolerably com¬ 
mon, one of which is of a uniform Prussian blue colour, 
whilst the other is of a uniform red. In the blue species the 
blue pigment is confined to the superficial structures, and is 
most abundant in the cells containing the rod-like bodies. 
It is insoluble in alcohol. It changes when acidified with 
dilute hydrochloric acid to a red, and is soluble in acidified 
alcohol. Neither the red nor the blue pigments yield ab¬ 
sorption bands in the spectrum. The pigment can be 
rendered blue or red by being made alkaline or acid any 
number of times. 
It was thought possible that the red species -would be 
found to contain the same pigment as the blue one in the 
acid condition, since the two species are exactly alike in 
form and occur together, but such was found not to be 
the case. The red form contains red pigment which does 
not turn blue on being rendered alkaline, and which is in¬ 
soluble in acidified alcohol. 
Etcone .—A species of Eteone was obtained from 1127 
fathoms, lat. 4P57 0 N., long. 9'42°, which had a bright 
