1. A Chromosome study of four species and a hybrid of the killifish genus Fundulus (Cyprinodontidae)

   • T. R. Chen
   • F. H. Ruddle

   OriginalPaper Pages: 255 - 267

2. Cytological localization of DNA complementary to ribosomal RNA in polytene chromosomes of Diptera

   • Mary Lou Pardue
   • Susan A. Gerbi
   • Joseph G. Gall

   OriginalPaper Pages: 268 - 290

3. An electron microscopic study of the etiology of hybrid sterility in Drosophila paulistorum

   • R. P. Kernaghan
   • L. Ehrman

   OriginalPaper Pages: 291 - 304

4. Meiosis in Coprinus

   • B. C. Lu
   • N. B. Raju

   OriginalPaper Pages: 305 - 316

5. Natural variation in nuclear characters of meristems in Vicia faba

   • M. D. Bennett

   OriginalPaper Pages: 317 - 335

6. Aberrationsverteilung nach Einwirkung von Myleran auf menschliche Chromosomen in vitro

   • Erich Gebhart

   OriginalPaper Pages: 336 - 348

7. Genetic inactivity of heterochromatin and heteropycnosis in Microtus agrestis

   • M. Sieger
   • F. Pera
   • H. G. Schwarzacher

   OriginalPaper Pages: 349 - 364

8. Specific nuclear DNA amounts in toads of the genus Bufo

   • Konrad Bachmann

   OriginalPaper Pages: 365 - 374