CHROMATOLOGY OF BLOOD OF SOME INVERTEBRATES. 483 
has made observations on its coagulation ; he does not, however, 
say anything about its spectroscopic characters. 
I named this pigment echinochrome and have lately 
made several observations on fresh specimens of Stron- 
gylocentrotus livid us, which I was able to procure alive 
in considerable quantity. On opening a specimen a fluid 
of a pale red colour exudes from the perivisceral cavity ; it 
sometimes has a violet tinge. In a short time a clot forms ; 
this becomes gradually darker in colour and it contracts more 
and more, until all its connections with the side of the contain- 
ing vessel are broken, and it finally shrinks into a small brown- 
red mass. The corpuscles are carried down by this clot and it 
is to them, not to the plasma, that the colouring matter 
belongs. Geddes 1 has shown that the coloui’less, finely granular, 
pale corpuscles run together to form plasmodia, and that it is 
to their fusion that the clotting is due. 
The corpuscles present all degrees of colouration, from a 
brilliant lake red, through a pale orange, to colourless. The 
red ones are nucleated and of irregular shape, and rapidly 
throw out amoeboid processes, so also do the others. The 
nucleus is strongly refracting and gives the corpuscle the 
appearance of a round hole having been punched in it. The red 
corpuscles measure from — gV^ -th inch in long diameter x - g - ^o 0 th 
in short, down to -g-glg-g-th in long x g-gy-g-th in short, while several 
measure ^t -g-th in both diameters. The pale ones 0 th 
x ^g -g-th down to - g - Q^ - g th x -g-gVo^ > tatter are multi- 
nucleated. 2 
The pigment itself in the fresh state showed no distinct 
bands but treated with caustic potash in the solid condition the 
colour changed to dark purple and showed the bands of sp. 1, 
Chart II. 
It seems to me that the deepening of colour which echino- 
chrome undergoes on exposure to the air must be in part due 
to the oxidation of a chromogen, if so we may infer the 
existence of such, and name it echinochromogen. 
1 Loc. cit. 
2 I think the red corpuscles only differ from the white in possessing pigment. 
