Does salinity influence the number of vertebrae developing in fishes?

Using the cyprinodontid fish, Fundulus majalis, five lots of 44 embryos each were reared in jars from gastrulation to hatching in a controlled-temperature room at five different salinities (16, 21, 26, 31 and 36‰). Comparisons of mean vertebral counts show no statistically significant differences occurring between them and thus no salinity influence upon vertebral number is indicated. The literature from the field of salinity influence upon vertebral number in fishes is reviewed and it is concluded that there is little evidence, from the field or the laboratory, to support the generally expressed acceptance of salinity as an important environmental factor known to modify vertebral number in developing fishes.