Knight —28 — Dictionary 



Chromoplast, Chromatophore. — In plants, a pigmented plas- 

 tid (particularly if not a chloroplast) ; in animals a pigment 

 cell. 



Chromosomal Chimaera. — A chimaera the components of 

 which do not have the same chromosome number. 



Chromosomal Fibres. — "Fibre bundles connecting the tiny 

 granules called 'spindle spherules' (important parts of the 

 centromere) with the poles. These chromosomal fibres have 

 by many authors been regarded as intimately involved in 

 chromosomal movement as traction fibres for the chromosomes" 



(OSTERGREN & PraKKEN). 



Chromosome Arm. — A segment between the spindle attach- 

 ment and either end of the chromosome. 



Chromosome Bridge. — A dicentric chromatid the two cen- 

 tromeres of which move towards opposite poles at the first 

 division so that the chromatid remains as a 'bridge' between 

 the anaphase chromosomes. 



Chromosome Complement. — A collective term for the group 

 of chromosomes in a single nucleus whether somatic or gametic. 



Chromosome Complex. — A set of chromosomes having a 

 given segmental arrangement. 



Chromosome Cycle. — All the changes which take place in 

 the chromosomes of an or'ganism from fertilization to gameto- 

 genesis. 



Chromosome Map. — A diagram of the relative position of 

 the genes in a chromosome, cf. Cytogenetic Map. 



Chromosome Matrix. — A chromophobic membrane enclos- 

 ing the chromosome proper. 



Chromosome Number. — The number of chromosomes in the 

 nucleus of a cell, the somatic number (2n) appertains to body 

 cells and the gametic number (n) to sex cells. 



Chromosomes. — Chromophilic bodies, typically constant in 

 number in any particular species, into which the nucleus re- 

 solves itself during cell division. 



Branched . Chromosomes in which the chromatids 



fork dichotomously, either at the spindle attachment or else- 

 where (White 1937). 



Ring . A chromosome whose two ends are fused to 



form a continuous circle. 



Chromosome Set. — The whole complement of chromosomes 

 present in, or derived from, the nucleus of a gamete. 



Chromosome Thread. — The thread, consisting of centro- 

 mere, chromomeres, achromatic connective thread and, perhaps, 



