ANTMAI. IMtODUCTTON. 1109 



The results of the oxiiorinionts in sex inliciit.iiicc witli ("iiinrios and tbo moth 

 .1. grossithiridlii are closely parallel, th(> ft'iiialcs eoiisulered (o ho heterozygous 

 ill sex, fenialeness heing deemed dominant, and the male as homozygous in the 

 ahsence of femaleness. The hlack-eye character of canaries is a dominant and 

 llie pink-eye characlcr a recessive. "Whatever may he the truth regarding 

 the transmission of sex. there is no escai)e from the remarkahle conclusion that 

 just as the normal females of the moth .1. (;r"ssiil<iri<it(i are in reality hybrids 

 in the lacticolor character, so the ordinary lil.ick-eycd hen canaries are hybrids 

 in the pink-eye character." 



The heredity of sex, II. C. Punnett and W. Bateson (»S'cJf«co, n. scr., 27 

 (If)OS), Xo. G!)S. pp. 7<S J-7<s'7' ) . — In this article Mendelian tluvn-ies of sex are 

 discussed. The authors believe that the sex determinants behave as Men- 

 delian allelomorphs, females being donnnant, that female individuals are 

 heterozygous in respect to sex- and males homozygous, and that at least in some 

 cases when two donunant factors coexist there is a repulsion between them 

 such that each gamete takes one or other of these two factors, not both. 



Secondary sexual characters, K. MiJLr.EB {Das Problem dcr ^ckiindurcn 

 (icsclilcclitsiiurkiiKilc unil die Tirrziiclit. Stuttgart, 190S. pp. S'.t). — This is an 

 expansion of two lectures, in which the differences between the sexes in animals 

 are discussed. 



Recessive characters, C. B. Davenport (Science, n. ser., 28 (1908), Xo. 

 12'), p. '!2'.i). — A cow without a trace of body hairs giive birth to a calf with 

 the ordinary hairy coat. " This result indicates that the i)resence of the hairy 

 follicles is donunant over their absence. This adds another case to the law that 

 the presence of a quality is dominant over its absence or that a retrogressive 

 or retarded conditi<»n is recessive to the more developed conditions." 



Degeneration, albinism, and inbreeding, C. B. Davenport {Science, n. ser., 

 28 {1!)08), No. 718, pp. .'i-').'i, .).jJ). — The author enunciates certain principles 

 which aid in understanding the reason for the degeneration which sometimes 

 follows the practice of inbreeding. "When the two parents have any organ or 

 (piality A in two conditions, A+ and A — , of which the former is a highly 

 developed or progressive condition, the latter a poorly developed or even absent 

 condition, the former condition will regularly dominate over the latter. . . . 

 When both parents have an organ in a low condition of development it will be 

 so also in all of their children. This principle explains the i)ersisting or in- 

 creasing degeneration in the descendants of two degenerate parents." 



Another class of degeneration is albinism, which is not a sport but a neces- 

 sary, predictable result of certain combinations of gametes. "The only part 

 that inbreeding plays is to make more probable the necessary combination of 

 gametes. The degeneration in this case follows from the iniion of two negative 

 factors in dihybrids, and this is a comnum cause of degeneration." 



Breeding experiments with rats, T. H. Morgan {Amcr. Nat., ^3 (1909), Xo. 

 '>07, lip. 182-185). — This is a report of some experiments in crossing rats to 

 determine how far the Mendelian lines of discontinuous inheritance ai)i)ly to 

 wild varieties and si>ecies. In cros.ses of the black rat with the gray roof rat 

 black is dominant to gray, whichever way the cross is made. All attempts thus 

 far to cross the bl:ick rat or the mof mt with the .Norway rat have failed. 



The chondriosomes as bearers of the hereditary qualities, F. Meves {Arcli. 

 Mihros. Anal. ti. HnttcicldHUfisycschichte, 72 {1908), Xo. }, pi>. SlC-Sln, i>ls. ', : 

 abs. in Anier. Xat., J,3 {1909), Xo. 507, pp. 190-192).— The author linds a large 

 number of independent structures in the cytoplasm of the chick eml)ryo at about 

 the third day of incubation, which he calls "chondriosomes." He thinks that 



sssuo— No. 12— O'J G 



