1246 METABOLISM OF LIPOIDS, STEROLS, [pt. iii 



The subject was evidently ripe for further work. Needham & 

 Needham in 1929, working on the Cahfornian sand-dollar, Dendraster 

 excentricus, and on a starfish, Patiria miniata, estimated the phosphorus 

 micro-colorimetrically in each of Plimmer & Scott's fractions, either 

 after incorporation of the material with anhydrous calcium sulphate, 

 or after extraction with trichloracetic acid. Table 176 summarises 

 their results : 



Table 176. 



Plaster-of-paris method 



Water- 

 Ether- soluble Pyro- 

 soluble inorganic phosphate 

 P P P 



Dendraster excentricus (mgm. per gm. dry weight) : 



Unfertilised eggs 0-422 2-04 



Gastrulae 0-77 323 



Plutei 0-75 319 



% of the total phosphorus: 



Unfertilised eggs 6-05 



Gastrulae 8-75 



Plutei 7-90 



Patiria miniata (mgm. per gm. dry weight) : 

 Unfertilised eggs 2-14 1-32 



Bipennaria larvae 1-09 i-ii 



% of the total phosphorus : 



Unfertilised eggs 32-20 19-80 

 Bipennaria larvae I7*75 18-05 



29-4 

 36-8 

 33-6 



0-950 



o-8o 



1-53 



13-65 

 9-1 

 16-1 



085 

 1-07 



12-8 



17-4 



Stable 

 water- 

 soluble 

 organic 

 P 



0-27 

 0-29 

 1-29 



39 

 3-3 

 13-6 



1-28 

 1-30 



19-2 

 21-1 



Total 



water- Phospho- Nucleo- 



soluble protein protein Total 

 P P P P 



3-26 

 4-32 

 6-01 



46-95 

 49-19 

 63-30 



3-45 

 3-48 



51-8 

 56-5 



0-84 

 037 



0-20 



4-2 



Trace 



None 



Trace 



None 



2-22 

 3-36 

 2-54 



32-0 

 38-2 



26-7 



1-04 

 1-56 



1565 

 25-40 



6-94 

 8-80 

 9-50 



lOO-O 



1000 

 loo-o 



6-64 

 6-15 



lOO-O 

 lOO-O 



Trichloracetic acid method 



Water- 

 soluble 

 inorganic 

 P 



Unstable 

 water- 

 soluble 

 organic 

 p* 



Dendraster excentricus (mgm. per gm. dry weight) : 

 Unfertilised eggs 1-645 0-036 



Gastrulae 1-274 0-067 



Plutei 0-382 0053 



Stable 

 water- 

 soluble 

 organic 

 P 



0-941 

 0-665 

 1-360 



Total 

 water- 

 soluble 

 P 



2-62 

 2-02 

 1-80 



Possibly creatine phosphate. 



Attention may be first directed to the rise in total phosphorus 

 which the sand-dollar egg exhibits during its development. The 

 figures given in Table 176, which are the sum of the various fractions, 

 were supplemented by direct estimations of total phosphorus, which 

 demonstrated the same phenomenon, for from an average of 760 mgm. 

 per cent, dry weight before fertilisation, it rose to 990 mgm. per cent. 



