98 Experimental Evolution, Variation, and Heredity 



is reached that gametic purity is not absolute. The inheritance of polydactylism in 

 the same species indicates that there is a variation in the potency of characters de- 

 pendent upon the degree of their development. 



No. 52. (Paper No. 7, Station for Experimental Evolution.) 

 DAVENPORT, C. B. Inheritance in Poultry. Octavo, v-j-136 pages, 17 plates. Pub- 

 lished 1906. (In cloth.) Price $1.50. 



This is a first study of thirteen sets of hybridizations between various pairs of 

 races of poultry. The inheritance of about thirty characters is considered and a 

 number of general topics discussed. Especial stress is laid on imperfection of 

 dominance and on the non-dependence of the dominant character upon the races 

 involved. The conclusion is reached that the patent form of a characteristic is 

 dominant over its "latent" (or absent) "allelomorph." 



No. 70. (Paper No. 8, Station for Experimental Evolution.) 

 MACCURDY, HANSFORD, and VV. E. CASTLE. Selection and Cross-breeding in relation 

 to the Inheritance of Coat-pigments and Coat-patterns in Rats and 

 Guinea-pigs. Octavo, 50 pages, 2 plates, 5 text figures. Published 

 1907. Price, $0.50. 



This is a study upon the problem of mutation vs. continuous variation. Pig- 

 mented rats have either a uniform pigmentation; or an "Irish" pigmentation, 

 lacking color on the middle belly; or the "hooded" pigmentation, lacking color 

 everywhere except on the head, and sometimes also back and shoulders. The more 

 extensive pigmentation tends to dominate in the offspring. The types appear to be 

 definite, but they may be modified by selection and hybridization so as to produce 

 hooded families with narrow back stripe or those with broad back stripe; and these 

 conditions may be exaggerated in successive generations. On the other hand, selec- 

 tion was unable to fix a particular pattern in guinea-pigs. The conclusion is reached 

 that "selection" is of importance in the improvement of races and that inheritance 

 is to some extent blending. 



No. 81. (Paper No. 9, Station for Experimental Evolution.) 

 MACDOUGAL, D. T., A. M. VAIL,, and G. H. SHULL. Mutations, Variations, and 



Relationships of the Oenotheras. Octavo, 92 pages, 22 plates, 73 text 

 figures. Published 1907. Price $1.00. 



Includes a continuation of the investigations described in No. 24. The identity, 

 distribution, and coefficient of mutability of Lamarck's evening primrose are dis- 

 cussed. The conclusion that newly arisen characters, such as the hypanthium, are 

 more variable than older ones is supported by the detailed studies made by Dr. 

 Shull, and illustrated in this paper by numerous tables and diagrams. The taxo- 

 nomic and physiologic aspects of several of the mutants and of native species of 

 Oenothera come in for a large share of attention. The overlapping distribution of 

 closely related species is described. Oenothera parviflora, long known in the gardens 

 in Europe, has been found in its native habitat in Maine, suggesting a similar origin 

 for many other species. The occurrence of two bud-sports is noted, one being the 

 mutative appearance on a branch of a recessive character in a hybrid combination. 

 Additional experiences with the method of ovarial treatment, discovered by Dr. 

 MacDougal in 1905, are given, and two forms secured in this manner were found 

 to be constant to the third generation, demonstrating that new characters may arise 

 by the action of external agencies upon the germ-plasm. Much historical matter of 

 interest is included. 



No. 95. (Paper No. 10, Station for Experimental Evolution.) 

 DAVENPORT, C. B. Inheritance in Canaries. Octavo, 26 pages, 3 plates colored to 



life. Published 1908. Price $0.80. 



Studies on inheritance of some characters in canary birds reveal mendelian 

 inheritance in this rather recently domesticated species. Crest dominates over its 

 absence and perfect crest over defective. Mottling results from yellow X green 

 and is a heterozygous character. Stress is laid upon the principle of localization of 

 units in a complex plumage pattern. 



