The vigour and male sterility of hybrids between the speciesTriturus vulgaris andT. helveticus

Angel, F. (1946)Faune de France. Reptiles et Amphibiens, Lechevalier Paris.

Benazzi, M. andLepori, N. G. (1949). Le gonadi nei maschi dell’ ibridoTriton cristatus × Triton vulgaris.Sci. genet. 3, 113.

Callan, H. G. andSpurway, H. (1951). A study of meiosis in interracial hybrids of the newt,Triturus cristatus.J. Genet. 50, 235.

Darlington, P. J. Jr. (1957).Zoogeography. The geographical distribution of animals. Wiley & Sons, New York; Chapman & Hall, London.

Dobzhansky, Th. (1950). Genetics of natural populations. XIX. Origin of heterosis through natural selection in populations ofDrosophila pseudoobscura.Genetics,35, 288.

Dobzhansky, Th. (1951).Genetics and the Origin of Species, 3rd edition., Columbia University Press, New York.

Dobzhansky, Th. &Koller, P. C. (1938). An experimental study of sexual isolation inDrosophila.Biol. Zentralblatt,58, 589.

Freytag, G. E. (1950). Über F1 Bastarde zwischen Fadenmolch (Triturus helveticus helveticus) und Teichmolch (Triturus vulgaris) insbesondere über Lantz’ Bastarde mit.T. v. meridionalis.Abh. Ber. Mus. Magdeburg,8, 2.

Freytag, G. E. (1954).Der Teichmolch. Die Neue Brehm—Bücherei Ziemsen, Wittenberg Lutherstadt.

Fühn, J. E. &Freytag, G. E. (1952). Über einige Besonderheiten des TeichmolchesTriturus vulgaris vulgaris in Rumänien und in der Türkei.Mit. Naturk. Vorgesch. Magdeburg,3, 89.

Haldane, J. B. S. (1948). Differences. Mind, LVII N. S. No.227, 294.

Haldane, J. B. S. (1955). On the biochemistry of heterosis and the stabilization of polymorphism.Proc. Roy. Soc. B. 144, 217.

Haldane, J. B. S. (1958). The Cost of Natural Selection.J. Genet.,55, 511.

Harland, S. C. (1936). The genetical conception of the species.Biol. Rev. 11, 83.

Hartmann, M. (1953).Allgemeine Biologie. 4th edition. Gustav Fischer Verlag, Stuttgart.

Hediger, H. (1950).Wild Animals in Captivity. Butterworths, London.

Lantz, L. A. (1934). Molchbastarde.Bl. Aquar. Terrark. 45, 2.

Lantz, L. A. (1947). Hybrids betweenTriturus cristatus Laur. andTriturus marmoratus Latr.Proc. Zool. Soc. Lond. 117, 254.

Lantz, L. A. andCallan, H. G. (1954). Phenotypes and Spermatogenesis of interspecific hybrids betweenTriturus cristatus andTriturus marmoratus.J. Genet.,52, 165.

Lerner, I. M. (1954).Genetic Homeostasis, Oliver and Boyd, Edinburgh & London.

Marquenie, J. G. M. (1950). De balts van de kleine watersalamander. De Levende Natuur,53, 147.

Maynard Smith, J., Clarke, J. M. &Hollingsworth, M. J. (1955). The expression of hybrid vigour inDrosophila subobscura, Proc. Roy. Soc. B. 144, 159.

Mayr, E. (1942).Systematics and the Origin of Species, Columbia University Press, New York.

Mayr, E. (1951). Speciation in Birds.Proc. Xth Int. Ornith. Cong. Uppsala 1950, 91.

Mertens, R. &Muller, L. (1940). Liste der Amphibien und Reptilien Europas.Abh. Senckenberg. naturf. Ges. 451, 1.

Muller, H. J. (1942). Isolating Mechanisms, Evolution and Temperature. Biological Symposia,VI, 71.

Muller, H. J. andSettles, F. (1927). The non-functioning of the genes in spermatozoa.Z. ind Abst. u. Vererb. 43, 285.

Rees, H. (1955). Heterosis in chromosome behaviour.Proc. Roy. Soc. B. 144, 143.

Smith, Malcolm (1951).The British Amphibians and Reptiles. New Naturalist, Collins, London.

Sonneborn, T. M. (1955). Heredity, Development and Evolution in Paramecium.Nature,175, 1100.

Spurway, H. (1945). Sex determination inTriturus vulgaris Linn. (taeniatus Schneid.)Amer. Nat. 79, 377.

Spurway, H. (1953). Genetics of specific and subspecific differences in European newts.Symp. Soc. exp. Biol. 7, 200.

Spurway, H. (1955). The sub-human capacities for species recognition and their correlation with reproductive isolation.11th Int. Ornith. Cong. Basel. 1954,Experientia, Supp. III. 340.

Spurway, H. (1957a). Heterosis and the evolution of reproductive isolation.Proc. Zool. Soc. Calcutta. Mookerjee Memor. Vol. 57.

Spurway, H. (1957b). The Relevance of Heterosis to Reproductive Isolation.Proc. Int. Genet. Symp. Tokyo and Kyoto, 1956.Cytologia Supp. 390.

Stebbins, G. L. Jr. (1950).Variation and Evolution in plants. Columbia University Press, New York.

Stebbins, G. L. Jr. (1958). The Inviability, Weakness, and Sterility of Interspecific Hybrids.Advances in Genet.,IX, 147.

Thoday, J. M. (1953). Components of Fitness.Symp. Soc. Exp. Biol.,7, 96.

Waddington, C. H. (1957).The Strategy of the Genes, Allen & Unwin, London.

Wallace, B. (1955). Interpopulation hybrids inDrosophila melanogaster.Evolution,9, 302.

White, M. J. D. (1946). The spermatogenesis of hybrids betweenTriturus cristatus andTriturus marmoratus.J. exp. Zool.,102, 179.

Wright, S. (1941). On the probability of fixation of reciprocal translocations.Amer. Nat.,75, 513.