The influence of external factors, chemical and physical, on the development of Fundulus heteroclitus

Abstract

T h e following experiments have been undertaken to determine to what extent the form of the embryo and its manner of development might be modified by external influences.I n a previous paper ('06), I have shown that lithium chlorid produces a definite effect on the development of Fundulus heteroclitus, as Herbst ('92) had shown for the sea-urchin and Morgan ('03) for the frog.During the past summer I have been able to show that these abnormalities are not only definite but specific for the lithium ion in its action on this egg.1 I n regard to the development of these eggs in fresh water, Loeb ('94) states: ''In fresh water the embryos hatch just as rapidly as in normal sea-water.O n the contrary, I have shown (Stockard,'o6), that these eggs are always slower to hatch in freshwater and further that the newly hatched young soon die when left in this medium.Sumner('o6) has also shown that the adult fish is unable to survive in perfectly fresh water.T h e fish is ahle to live in fresh water."