504 GLOSSARY 



AS'-TER. The radiating figure surrounding the centrosome in 

 a cell. 



AS-SIM-I-LA'-TION. Conversion of food substances by an or- 

 ganism into its own living substance. 



A-SYM'-ME-TRY. The condition where opposite sides are 

 unlike. 



AT'-A-VISM. The condition in which an individual resembles a 

 grandparent, or a more distant ancestor, more than one 

 of the parents. 



BI'-O-PHOKES. The ultimate units of life (Weismann). 



BI'-VA-LENT CHRO'-MO-SOMES. A pair of chromosomes, one ma- 

 ternal the other paternal, temporarily united. 



BLAS'-TO-COEL. The cavity within a blastula. 



BLAS'-TO-DER'-MIC VES'-I-CLE. A hollow sphere, formed from 

 the segmented egg of a mammal, which becomes attached 

 to or embedded within the wall of the uterus. 



BLAS'-TO-PORE. The mouth of a gastrula. 



BLAS'-TTJ-LA. A mass of cells, usually in the shape of a hollow 

 sphere, formed by repeated divisions (cleavages) of an 



egg- 



BLENDING INHERITANCE. Galton's term for that kind of in- 

 heritance in which the characters of the parents seem to 

 blend in the offspring. 



BRACH-Y-DAC'-TY-LISM. The condition of having abnormally 

 short fingers or toes. 



CELL. The fundamental unit of structure and function in all 

 living things. 



CEN'-TRO-SOME. The body at the center of radiations in a 

 dividing cell. 



CEPH'-A-LO-PODS. A class of mollusks which includes the squid, 

 cuttle-fish and devil-fish. 



CER'E-BRAL GANO'-LI-ON. The brain of an invertebrate 

 animal. 



CHARACTER. Any feature or property of an organism. 



CHOR'-DA. A cellular rod in vertebrate embryos which forms 

 the basis of the backbone. 



CHOR'-DATE. A member of the highest phylum of the animal 

 kingdom, including all animals having a chorda or back- 

 bone. 



