Congenital hydrocephalus in the mouse, a case of spurious pleiotropism. (With Eleven Text-figures) -- Hans Grüneberg

Two new mutant genes in the house mouse. (With Three Text-figures) -- Hans Grüneberg

The development of some 'leg genes' in Drosophila. (With Six Text-figures) -- C. H. Waddington

The structure and development of four mutant eyes in Drosophila. (With Six Text-figures) -- C. H. Waddington and R. W. Pilkington

Viability interactions between chromosomes of Drosophila melanogaster and Drosophila simulans. (With One Text-figure) -- G. Pontecorvo

A cytological study of Crepis fuliginosa, C. neglecta, and their F₁ hybrid, and its bearing on the mechanism of phylogenetic reduction in chromosome number. (With Plates 1--3 and Seventy-four Text-figures) -- H. A. Tobgy

Genetical and cytological studies of Musa. V. Certain edible diploids. (With Plate 4 and Twenty-five Text-figures) -- K. S. Dodds

Genetics of the Scapiflora section of Papaver. II. The Alpine poppy. (With 6 Text-figures and 2 Diagrams) -- A. C. Fabergé

Physiology of incompatibility in plants. III. Autopolyploids. (With Plate 5 and Two Text-figures) -- D. Lewis

The effect of ionization distribution on chromosome breakage by X-rays. (With Eight Text-figures) -- D. G. Catcheside and D. E. Lea

The inheritance of coat and nose colour in long-haired dachshunds -- A. J. Lea

The optomotor responses of some eye mutants of Drosophila. (With Two Text-figures) -- Hans Kalmus

Specific differences in Petunia. I. Incompatibility. -- K. Mather

Specific differences in Petunia. II. Pollen growth. (With Six Text-figures) -- A. J. Bateman

Specific differences in Petunia. III. Flower colour and genetic isolation -- K. Mather and P. M. J. Edwardes

The incompatibility sieve for producing polyploids -- D. Lewis

The genetics of the Wensleydale breed of sheep. III. Arithmetical aspects of selection -- F. W. Dry

The polygenes affecting the manifestation of scute in Drosophila melanogaster. (With One Text-figure) -- G. M. L. Haskell