Itl.VI.I.Mi'Mi.xT OF EGGS OF ARBACIA AM) CH.ETOPTERUS. 285 



mentation was progressing in a normal manner and at about the 

 same rate in all of the solutions. 



Five hours after the eggs had been fertilized a few larva? in the 

 YJ per cent, solution were moving slowly: at this time there was 

 no movement of any of the eml >ry< is in the other cultures or in the 

 control lot. A weak solution of asparagine, therefore, slightly 

 accelerates the development of the eggs of Chcrtoptcrus, if it be 

 ih.it an earlier movement of the embryos is indicativ e of a more 

 advanced stage of development. At the end of the sixth hour 

 the effect's ot the various solution- were MTV marked: the 

 embryos in the /,; per cent, solution were movin- moiv actively 

 than those in the control, and they seemed slightly better de- 

 veloped; the larva? in the other solutions were moving -lowly and 

 their development lagged considerably behind that of the control 

 larva-. After eight hours the larva- in the I per cent, solution 

 were all at the bottom of the dish and evidently d\in^: no ab- 

 normal types of larva? could be detected amoiu the li\ in^ form-, 

 and none were found in preserved material that was examined 

 Liter. The embryos in the other solution- \\ere swimming at 

 the surface after ten hours, but none of them li\ed more ihan 

 i \\eiuy-four hours. 



(ilycocoll. In the strengths of solution- u-.-d i, .1 and ,' 

 per cent.), this substance did not appear to ha\e .my effects 

 whatever on the eggs during the first twelve hour-. < >n the 

 >nd day the larva? began dying, and all of them had 1 >eeii killed 

 b\ the end of the third day. 



Altinin. Batches of Clh< eggs that had been artificially 



fertilized at lo.,V> A.M. on the mornin:; of Aui;ii-t >>, IIOM, were 

 put into various solutions of alanin (I, .', , ,',, and 3 ',, p i cent.) 

 at ii o'clock. The eggs in all of the cultures, including the 

 control, began segmenting at the same time, and all of them 

 developed at about the same rate during the next t \\ o hour-. 

 At 3.30 P.M. a number of swimming larvae were found in the ,',, 

 and in the 3 ^ per cent, solutions, but at this time there was no 

 movement of the l.irx.e in any of the other cultures. At 4..V> 

 I'M. ciliated larva? were present in great numbers in all of the 

 solution-; but the larva- in the I percent, -ohition could move 

 but -lowly, and soon all of them sank to the bottom of the di-h 

 and disintegrated. 



