GLOSSARY 



ACCESSORY 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. 



ALLELMORPH. Contrasting unit characters, or their corresponding genes. 



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-PHI-OX'-US. One of the lowest and simplest animals having a noto- 

 chord (backbone). 



AN-EN-CEPH'-A-LY. 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'-O-TYPE. A group of individuals all of which have the same Geno- 

 type (Johannsen). 



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. 



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