Cytology of Lepidosiren

I HAVE just seen the issue of NATURE of August 28, in which Prof. E. W. MacBride refers to an early work of mine on the spermatogenesis of Lepidosiren. Although a reply after such a long interval loses much of its point, his use of that work as a disproof of the chromosome theory of heredity is so surprising that I feel that a reply is desirable.