The tail-tip method for the cytological study of amphibian larvae is well adapted to the survey of large groups of animals ; it enables one to ascertain the incidence of heteroploidy rapidly and accurately. Such studies have been carried out, using larvae of Triturus viridescens (Fankhauser, '41, and other papers), Eurycea bislineata (Fankhauser, '39 ; Michalski, '48), Triturus pyrrhogaster (Fankhauser, Crotta and Perrot, '42), Triturus torosus (Costello and Henley, '49a)' and other forms.
The eggs of the salamander, Amblystoma punctatum (Ambystoma maculatum), have been used for embryological research over a period of many years, but no cytological studies involving larvae from a natural population have been reported. This is somwhat surprising, in view of the fact that egg masses of this form are so readly available in the eastern United States. Furthermore, the eggs are laid in large masses, and are admirably suited to development under laboratory conditions. It is probable that one of the reasons for the neglect of A. punctatum in studies of heteroploidy involves the fact that the tail-tips initially clipped from the young larvae are not very satisfactory for cytological study: they are rather heavily pigmented, and the interpretation of mitotic figures is therefore difficult. However, the regenerated tail-tips make beautiful preparations, and it has been possible 'Aided b7 a grant from the American Philosophical Society.