M.VELOPMENT OI EGGS '[ Akl:\<IA AND CBLETOPTERUS. 283 



at the surface of tin- solution, hut tlu-y had evidently reached their 

 maximum development and would -non die. The ^ per ivnt. 

 solution contained a con-idcrable number of swimming larvae, 

 but the-e larvae wen.- not in good condition and plainly -ho\\ed 

 the injurious effects of tin- K-u-in. A lar-c number of ciliated 

 embryos were found in tin- ^ per cent, solution, and they ap- 

 peared somewhat further adx.mced in development than tho-e 

 in the control culture. De-eiierative ch.in-^ - appeared in the-e 

 larva- in about twenty-four hours, ho\\e\er, and all of them 

 were dead within thirty hours. No unusual type- of lar\.e were 

 found in preparations of l\}< gs !i\< d .it variou- stages in 



their development. 



As it seemed possible that the solution- ot leucin einplo\ed 

 in the experiments described above might h.i\e been loo \\ ( , t k 

 to produce any alteration in the development of th . a 



second experiment was made in which a batch < ub- 



'd to the action of a I per cent, solution of leiicin. Tin 

 inented at the normal time, but two hours later their develop- 

 ment was found to be lagging behind that of th- in the 

 < ' 'iitrol culture. After four hours the rei.n-d.it ion in d< -\elopnn m 

 \\.i- very marked, and in some instance- tuo m m Md 

 fu-ed together. Loeb and Lillie ha\ - c noted ih.it the I'u-iou of 

 M \ eral embryos into giant forms is a phenomenon of fiv<|tn-nt 

 urrence when eggs of Chatopterus are treated \\ith poi.i iuin 

 -alt-. In twenty hours all of the larva? \\en- dr. id, .md > ili-- 

 inti-i.ited that it was impossible to pre-er\i- ,m\- mail-rial lit 

 li 'i -i udy. Sections of eggs fixed in earlit-r stages < >\ de\ elopmt-in 

 tailed to show any abnormalities except the oec.i-ion.il fu-ion of 

 i u o or more embryos. 



rosin. This substance was used on the ej gs "f ('liiitof>ti'rns 

 in a -.Unrated solution which i- le than ,',, per cent. < >nly a 

 \"er\ tew of the eggs had segment i-d when the tir-t di\i-ion 

 curred in the control eggs. After four hours the tyn>-in culture 

 shoued all stages in development from the un-c^mcntcd 

 through to late segmentation, the nio-l ad\anced ci;;^- 

 apparently at the same stage of de\elo])iuent a- tli< of the 



(oiurol. All of tin- emlir\o- in the tyro-in solution died \\ithin 

 twenty-four hours after the experiment \\.i- started. Pre-erxed 



