DR. C. A. MAC MUNN ON MTOH^EMATIN AND THE HISTOMMATINS. 269 
muscle, or with that of the blood-free pancreas of a cat, a most striking resemblance is 
apparent. Such a statement may appear startling but is nevertheless true, as I have 
convinced myself by repeated examination and measurements. The eggs of most 
animals when examined by this method show the lutein band or bands, but in Ur aster 
the spectrum is entirely different and belongs to a typical histohsematin.* * * § We find a 
narrow band before D, two still nairower between D and E, and two others faint 
nearer the violet, spectrum 1, Chart I. They gave the following readings (approxi¬ 
mately) : — 
1st band 
2nd band 
3rd band 
4th band 
X 613 to X 591, or 593, 
X 569 „ X 560, 
X 556 „ X 548-5, 
X 537 „ X 516 (about). 
A great number of specimens were examined and in all the same spectrum observed. 
The stomach-wail likewise gave a distinct spectrum which bears a close resemblance 
to heemochromogen, spectrum 2, Chart I. The first of these bands read X 566 to X 558'5 
(approximate). There is evidence to show that elsewhere in this species a histo- 
hsematin occurs ; thus the spectrum of the ampullae resembles that of the stomach-wall. 
I tried by various solvents to isolate these pigments but failed. The colour of the 
organs in which they occur is a more or less pale-yellow. The bands appear to 
become darker on treatment with reducing agents, and less shaded on exposure to the 
air, although the change from the oxidised to the reduced state is not easily brought 
about. 
In the integument of Uraster rubens, when it has a brownish tint, the presence of 
hsematoporphyrint can be easily proved, and as the only pigments present in the 
animal are enterochlorophyll in the radial coeca, histohsematins in the tissues, and a 
lipochrome here and there, and as hsematoporphyrin cannot be obtained from entero¬ 
chlorophyll or from the lipochromes, it is highly probable it is a metabolite of the 
histohsematins; or what is less likely that these pigments may be derived from 
the same radical. 
In Ophiactis virens , M. F(Ettinger| states that he found haemoglobin, but Kruken- 
berg § thinks this observation incorrect, and that the water-vascular system of this 
echinoclerm probably contains a pigment related to the bile-haematin (“ helico-rubin ” 
* A small quantity of a lutein (=lipochrome) can be got out of the eggs by absolute alcobol. Tte 
male generative organs contain histohsematin as well as the eggs. 
t It occurs in tbe integument in the condition of hajmatoporpbyrin as such, as can easily be proved by 
examining tbe scraped-off pigment with the microspectroscope. I first showed its presence in this 
situation. Proc. Birm. Phil. Soc., vol. iii., p. 378. It can be isolated by digesting the integument in 
alcohol and sulphuric acid. Journ. Physiol, vol. vii., pp. 240-252. 
| Bull. Belgian Acad., No. 5. 
§ “ Grnudziige einer vergleichenden Physiologie der Earbstoffe,” Ac., p. 134. 
