156 ALPHABETICAL COMPILATION 



1943, p. 81; 1952, p. 96; E. B. Harvey, 1945). The cations arranged according to 

 their effect in decreasing viscosity (better stratification) are 



Ca > Mg > sea vv'ater > Na > K (E. B. Harvey, 1945, p. 74) 



Ca > Mg > sea water > K > Na > NH4 (Heilbrunn, 1928, p. 147). 



Added Ca decreases viscosity (Wilbur and Recknagel, 1943). 



Breaking of eggs. — Isotonic CaCla causes eggs to break with centrifugal force less 

 readily than in sea water; the better stratified, the less easily they break. The cations 

 arranged for ease in breaking are in the reverse order to that given above for de- 

 creasing viscosity (E. B. Harvey, 1945). 



Calcium-Free Sea Water. — As compared with eggs in sea water, no difference in rate 

 of stratification, indicating change in viscosity, could be detected by observation 

 with a double head centrifuge microscope (E. B. Harvey 1933 b) (Table 16). Wilbur 

 and Recknagel (1943) found increased viscosity when calcium was removed from 

 the sea water by potassium citrate. According to Kriszat and Runnstrom (1951) 

 viscosity is increased in calcium-free sea water in Ps. miliaris. Unfertilized Arbacia 

 eggs elongated more and broke more readily in calcium-free sea water, and fertilized 

 eggs broke more readily than in sea water (E. B. Harvey, 1933 b, 1945). Shapiro 

 (1941) found that unfertilized eggs elongated more and rounded up more rapidly 

 in calcium-free sea water, whereas they elongated less and rounded up more slowly 

 in increased calcium (3 times amount in artifical sea water). 



Parthenogenesis. — Caused by adding CaClj to the sea water (Loeb, 1900 a, 1913 a, 

 p. 59, etc.) ; by 0.3 M CaClg (Hollingsworth, 1941). But R. S. Lillie (1910, 191 1 a, b, 

 1914 a) found that isotonic CaCIa did not activate, and prevented activation by 

 NaCl. Ca is necessary for activation by ultraviolet light (Heilbrunn and Young, 

 1930; Heilbrunn and Mazia, 1936) and other parthenogenetic agents (Moser, 

 1939 b). For the necessity of calcium for parthenogenesis in general see Tyler (1941 a, 

 p. 322) and Heilbrunn (1943, p. 661). 



Longevity of Egg. — Increased by reduction of Ca (Schechter, 1937). 



TABLE 16 



CALCIUM-FREE AND ARTIFICIAL SEA WATER 



M. B. L. at Woods Hole, Mass. as prepared in Chemical Room, for salinity 



31 (grams per liter) 



NaCl KCl CaCla.aHjO MgClj.eHjO MgS04.7H20 NaHCO- 



grams per 



Hter 24.72 0.67 1.36 4.66 6.29 0.18 



ml. of I M 



solution* 423.0 9.00 9.27 22.94 25.50 2.15 



pH of sea water at Woods Hole 8.14 (Ball and Stock 1937). A is 1.805. 



(Herbst (1900) at Naples, for salinity 38 (grams per liter) 



NaCl KCl CaCla MgSOi MgHP04 



3% + o.o7% 0.08% 0.13% 0.66% in excess, 



to replace for 



CaClj alkalinity 



Calcium can be removed from sea water with potassium oxalate (or citrate), about 1.5 gm. 



per liter of sea water. 

 For other formulae for calcium-free sea water, see McClung's Microscopical Technique, 3rd ed., 



P- 559> '950; Horstadius, 1935 and Tyler, 1953. 



* Total mixture to be diluted to one liter. 



