506 GLOSSARY 



Di-hy'-beid. The offspring of parents differing in two char- 

 acters. 



Di-o-nae'-a. An insect-catching plant, the "Venus Fly-trap." 



Dip'-ioiD. The full number of chromosomes found in the ferti- 

 lized egg and in all cells derived from this, except the 

 mature germ cells. 



Dominant chaeacter. A character inherited from one parent 

 which develops to the exclusion of a contrasting character 

 of the other parent. 



Dhos-oph'-i-la. a genus of fruit-flies. 



Du'-PLEX FACToas Or chaeacteb. a condition where the de- 

 terminers for a character are derived from both parents. 



E-CHi'-NO-DEEMS. A phylum of marine animals which includes 

 star-fishes and sea-urchins. 



E-col'-o-gy. The science which deals with the relations of 

 organisms to one another and to environment. 



Ec'-TO-DEEM. The outer layer of cells of an embryo which 

 gives rise to epidermis, sense organs and nervous system. 



Em-bey-og'-e-ny. Early development of an egg leading to 

 the formation of an embryo. 



En'-do-deem. The inner layer of cells of an embryo, which 

 gives rise to the digestive cells of the alimentary system. 



Ep-i-gest'e-sis. The doctrine that the germ is simple and 

 homogeneous and that development consists in the for- 

 mation of complex parts from the simple germ. 



EauATiON-Divisioif. An ordinary nuclear division in which 

 each chromosome divides equally. 



Eu-gen'-ics. The system of improving races by good breeding. 



Eu-THEif'-ics. The system of improving individuals by good 

 environment. 



Ex-o-gas'-teu-la. a gastrula with the endoderm turned out 

 instead of in. 



Factoe. a specific germinal cause of a developed character. 



Feetilization. The union of male and female sex cells. 



FxA-GEL'-tuM. A vibratile thread of protoplasm which serves 

 as an organ of locomotion. 



Fluctuations. Variations which are not inherited. 



