Food of the Silver Fox Vulpes Chama

Eggs and sperm of Parechinus have been placed in sea water containing 1, 10 and 100 p.p.m. ammonium nitrate and the percentage fertilization as well as the subsequent development of the embryos compared with controls. At 10 and 100 p.p.m. there is a marked reduction in fertilization. Abnormal forms are common at 100 p.p.m. and some 95% of the population fail to reach the gastrula stage.