520 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-thy. 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-phores. 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'-tu-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 Gang'-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. 



