GLOSSARY 



Accessor* chro'-mo-some. An odd chromosome which is found in only 



half of the spermatozoa of certain animals; see "sex-chromosome." 



A-chro'-ma-tin. The non-staining substance of the nucleus as contrasted 

 with the chromatin. 



A-chon'-dro-pla-sy. A condition in which the long bones cease to grow 

 in length at an early age thus producing a dwarf with large body and 

 head but short limbs. 



Acquired Character. A character, the differential cause of which is en- 

 vironmental. 



Alternative Inheritance. Galton's term for a doubtful kind of inheri- 

 tance in which all characters are derived from one parent. In present 

 use, Mendelian inheritance. 



Am'-ni-on. One of the embryonic membranes of higher vertebrates. 



Am-piii-ox'-us. One of the lowest and simplest animals having a noto- 

 chord (backbone). 



An-en-ceph'-a-ev. The condition of a brainless monster. 



Animal pole. That pole of an egg at which the polar bodies are formed. 



An'-la-ge. The embryonic basis of any developed part. 



A-or'-ta. The great artery arising from the heart. 



Ar'-chi-plasm. The deeply staining plasm surrounding the centrosome. 



As'-ca-ris. A genus of round worms which are intestinal parasites. 



As'-ca-ris meg-a-lo-ceph'-a-la. A parasite in the intestine of the horse. 



As-cid'-i-an. A "sea-squirt" ; one of the lowest types having a notochord, 

 or elementary backbone. 



As'-ter. The. radiating figure surrounding the centrosome in a cell. 



As-sim-i-la'-tion. Conversion of food substances by an organism 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 grand- 

 parent, 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 maternal the 

 other paternal, temporarily united. 



Blas'-to-coel. The cavity within a blastula. 



