1072 KXI'KUIMKX'I' STATION RECORD. 



suits. Ill iiiniiy orsxiiiiisiiis llic IVrtilizi'd o;:.^ is pi-cdctcriuiiuHl as male, fpinalo, 

 or hernial ill rod ite. The sex of the individual is mialterahle by external condi- 

 tions. Double monsters, multiple embryos, and secondary embryos are always 

 the same sex when derived from the same eiiu:- Cytolo;;ical studies on the 

 dimorphic spermatozoa of insects, niyriopods, and arachnids show that sper- 

 matozoa which do not contain the accessory chromosome are not f<mctionaI. 



The author points out the difficulties in the way of accepting the Mendelian 

 theories of sex heredity sug.uested by Castle, Correns, and Rateson, and he pro- 

 poses the provisional hypothesis that a sinfj;le X-element (in the simplest cases 

 represented by the accessory chromosome) iu itself causes or determines the 

 male tendency, while two such elements in association create, or at least set free, 

 the female tendency. Evidence now indicates that in diecious organisms sex 

 production is primarily adai>ted for the production of males and females in 

 equal number. 



A new color variety of the guinea pig, ^Y. E. Castle (Science, n. so:, 2<S 

 (IVOS), Xo. 712, pp. 250-252). — The author believes that color inheritance in all 

 its iihases seems to conform to Mendel's law of heredity. In guinea pigs there 

 are three different kinds of pigments, black, brown, and yellow. In the wild 

 guinea pig these pigments are so placed on the individual hair as to give it a 

 banded appearance. The banding is inherited as a factor independent of the 

 colors present. Any mating that brings all four factors together will result in 

 a return to the original color of wild forms. If this hypothesis is correct il 

 ought to be possible to produce a color variety of guinea pigs not previously 

 known. 



True to this prediction the author obtained a new Aariety in the following 

 way : " Agouti-colored individuals were crossed with chocolates. The young 

 were all agouti-colored. But when mated with each other these agouti young 

 produced offspring of four sorts, agouti, black, cinnamcn-agouti, and chocolate. 

 The cinnamon agoutis are a sharply defined and unmistakable new variety, 

 differing from the wild type iu the total absence of black pigment from the eye, 

 the skin of the extremities, and from the hair. . . . We are able to pre- 

 dict the production of new varieties, and to produce them. AVe must not, of 

 course, in our exuberance, conclude that the powers of the hybridizer know no 

 limits. The result under consideration consists, after all, only in the making of 

 new combinations of unit characters, but it is much to know that these units 

 exist and tliat all conceivable combinations of them are ordinarily capable of 

 production. This valuable knowledge we owe to the discoverer and to the re- 

 discoverers of Mendel's law." 



Inheritance in canaries, C. li. Daventort {Carnegie Inst. M'o.sJiiii<jl()n Pub. 

 !I5, pp. 2(j, ph. 3). — The author bred crested and noncrested canaries of tlie 

 short or German type to see if the crest was alternative and dominant as in 

 the case of poultry and pigeons, as previously reported (E. S. It., IS, p. 271). 



Of 102 offspring of 2 noncrested parents all were noncrested. Crested off- 

 spring were obtained from crested parents. Of G6 offspring from 2 heterozygous 

 crested parents, IS were noncrested and 4S crested. This is very close to the 

 25 and 75 per cent which theory calls for. A heterozygous parent was crossed 

 with a crested parent and the result was 52 noncrested and 42 cri'sted offspring. 

 The crest is thus found to be dominant in canaries as well as in other birds. 

 The advice of practical men that 2 crested birds should not be mated as they 

 produce baldness is based on an error. 



The inheritance of plumage color was studied witli green, yellow, lizard, and 

 cinnamon coloi"ed canaries. Crosses were also made between the European 

 goldfinch and the yellow canary, with the following results: 



