174 ALPHABETICAL COMPILATION 



tion, Aug. 1954). In amoebocytes, eggs and plutei, is in chromatophores, though 

 R. S. LilHe (191 ib) thought some is diffused through the cell. Occurs only in 

 Echinoidea among the Echinoderms (Fox and Scheer, 1941). 



Amount. — In eggs, 0.58 gm. pigment per 100 cc. eggs packed by centrifuging. In 

 amoebocytes, 3.78 gm. per 100 cc. of packed body cells; same from ^J and 5. In test 

 0.19 grams echinochrome per 100 gm. Average $ contains 38 gm. echinochrome, ^ 

 half this (Ball and Cooper, 1949). 



Chemical Structure. — CijHjyO, (Ball, 1936, Ball and Cooper, 1949). Same for 

 A. lixula (Lederer and Glaser, 1938; Hartman, Schartau, Kuhn, and Wallenfels, 

 1939). It is a polyhydroxynaphthoquinone, which in the eggs is bound to proteins 

 (Kuhn and Wallenfels 1939; Wallenfels and Gauhe, 1943 in A. lixula). 



According to some investigators echinochrome contains copper (Glaser, 1923) ; fats 

 (McClendon, 1909a, 1912a) ; fatty acids (Navez, 1939). 



Soluble. — In acetone, absolute alcohol, ether (McClendon, 1912 a); in chloro- 

 form, ether, benzene; insoluble in petroleum ether (Ball, 1934, 1936). Same for 

 A. lixula (Lederer and Glaser, 1938); same for S. purpuratus (Tyler, 1939). 



Adsorbed. — On charcoal (Hinrichs, 1927); on norite (Navez and DuBois, 1940). 



Extraction and Crystallization. — Of echinochrome in A. punctulata (McClendon, 

 1912a; Cannan, 1927; Ball, 1934, 1936; Ball and Cooper, 1949). Forms reddish or 

 orange needle-like crystals (McClendon, 1912a; Ball, 1934). Same for A. lixula 

 (Lederer and Glaser, 1938; Glaser and Lederer, 1939; Kuhn and Wallenfels, 1939) ; 

 and for S. purpuratus (Tyler, 1939). 



Color Change. — Red or orange in acid, violet or green in alkali (McClendon, 

 1910a, b). Red to yellow; pK^' value at 26 °C. calculated to be 6.38; unstable in 

 alkaline ranges from pH 6.8 (Ball, 1936; Ball and Cooper, 1949). In sodium citrate 

 at pH 7.4 turns dirty brown then clear green (D. L. Harris, 1943). Faded by ultra- 

 violet (Hinrichs, 1927; E. B. H., 1950 unpub.). Change of color used as a natural 

 indicator of pH in A. lixula (Vies and Vellinger, 1938). 



Absorption Spectra. — Studied by MacMunn (1883, 1885) in other species. In 

 A. punctulata by McClendon (1912a) ; Ball (1936) ; Ball and Cooper (1949). Absorp- 

 tion spectra same for eggs, amoebocytes, and tests (McClendon, 1912a); also for 

 spines and plutei (Ball and Cooper, 1949). Red acid form has peaks at X 255, 335, 

 and 475 m[i.; yellow form at X 275, 400 and 475 m\L (Ball, 1936; Ball and Cooper, 

 1949). For absorption spectra of ^. lixula see Runnstrom (1928 b); Lederer and 

 Glaser (1938); Kuhn and Wallenfels (1939). 



Oxidation-Reduction. — Echinochrome does not form a dissociable compound with 

 oxygen, but can be reduced (with sodium hydrosulphite) and re-oxidized. E^ = 

 + 0.1995 volts; and E^' at pH 7 and 30 °C. = — 0.221 volts (Cannan, 1927). For 

 A. lixula see Lederer and Glaser (1938). In eggs, it is not reduced by anaerobiosis 

 (McClendon, 1910b, 1912a; Cannan, 1927; Korr, 1939, p. 83; and Ball, same 

 paper, p. 92). With regard i^ a species having very little pigment, Cannan (1927, 

 p. 187) says "it would appear that E. esculentus holds its pigment in the partially 

 reduced state, since the perivisceral fluid is almost colorless but rapidly turns red 

 when removed from the animal. In Arbacia, the echinochrome is in the oxidized 

 state and I know of no observation of the spontaneous decolorization of the cells 

 in vivo." 



Function. — Not known. Was thought to be an oxygen carrier in other species by 

 Geddes (1880) ; MacMunn (1885) ; Griffiths (1892 a) ; but this was denied by Cu^not 

 (1891a). Has been questioned for A. punctulata by McClendon (1912a); Cannan 



(1927)- 



Stated to increase respiration, 16 times, in Paracentrotus lividus and Sphaerechinus 

 granularis (Friedheim, 1932), but this was denied by Tyler (1939) for S. purpuratus. 



Stated to be a sperm activating agent in A. lixula (Hartman, Schartau, Kuhn, and 

 Wallenfels, 1939), but this was denied by Tyler (1939) for Strongylocentrotus purpuratus 



