GLOSSARY 187 



Bacillus (L. bacillus, a little rod), lowest single-celled plant-organism. 



Bacterium (Gr. bakterion, a little staff), lowest single-celled plant- 

 organism. 



Biology (Gr. bios, life; logos, a discourse), the science of life. 



Biometrics, biometrical (Gr. bios, life ; metron, measure), the 

 statistical science of life. 



Biophor (Gr. bios, life; pherein, to bear), the smallest living unit of 

 the body (p. 63). 



Blastogenic (Gr. blastos, germ ; genes, producing), arising in the 

 germ (p. 96). 



Blastomere (Gr. blastos, germ ; meros, a part), a segment of the 

 dividing ovum. 



Blastula (Gr. blastos, germ) (p. 47). 



Castration (L. castratio), emasculation. 



Cellular (L. cellula, a cell), consisting of or pertaining to cells. 



Centrosome (Gr. kentron, a sharp point, centre; soma, body) (p. 32). 



Chsetopoda (Gr. chaite, hair; pous, pod-, foot), a class of worms, in- 

 cluding the earthworm, etc. 



Chromatin (Gr. chroma, colour) (p. 30). 



Chromomere (Gr. chroma, colour ; meros, part) (p. 58). 



Chromosome (Gr. chroma, colour ; soma, body) (p. 32). 



Class (p. 156). 



Conjugation (L. con, together; jugum, yoke) (p. 17). 



Consanguinity (L. con, with ; sanguis, blood), relationship by blood 

 (p. 118). 



Crustacea (L. crusta, rind), a large class of animals, including 

 lobsters, crabs, etc. 



Daltonism (named from the chemist John Dalton) (p. 112). 

 Darwinism, Darwinian (named from Charles Darwin), the theory 



of the " Origin of Species," by Darwin. 

 Degeneration (L. de, down ; genus, kind), deterioration. 

 Dementia (L. de, negative ; mens, mind) , mental enf eeblement. 

 Determinant (L. determinare, to determine) (p. 57). 

 Determinate (L. determinare, to determine) (p. 80). 

 Deviation (L. deviare, to deviate), a divergence (p. 154). 

 Diathesis (Gr. dia, asunder ; tithenai, to place), predisposition to 



particular diseases, as gout, etc. 

 Differential (L. differentia, a difference) (p. 77). 

 Dihybrid, dihybridism (Gr. di, twice ; L. hibrida, a mongrel), a 



double hybrid (p. 127). 

 Diptera (Gr. di, twice; pteron, wing), two-wmged^insects, as flies, etc. 



