xviii GLOBSABY OF TECHNICAL TERMS 



CAMBRIAN, the first epoch of the palaeozoic era, the characteristic 

 rocks of which are largely developed in North Wales 

 (Cambria). 



CARBOHYDRATES, a group of chemical compounds which contain 

 the elements carbon, hydrogen and oxygen, the two latter in 

 the proportion H 2 ; e.g., starch, sugar. 



CARBON DIOXIDE ( = carbonic acid gas), a gaseous compound of 

 carbon and oxygen, having the formula C02. 



CARBONIFEROUS (Lat. carlo, coal ; ferre, to bear), one of the 

 palaeozoic epochs, during which coal was deposited. 



CARPALS (Gr. nap-nds, wrist), the bones of the wrist. 



CARPELS (Gr. Kapiros, fruit), the modified leaves which form the 

 so-called ovary of a flower, from which the fruit arises. 



CASEIN (Lat. caseus, cheese), a proteid substance found in 

 cheese. 



CASTRATION (Lat. castrare, to castrate), the removal of the male 

 gonads or testes. 



CELL (Lat. cella, apartment, cell), a nucleated protoplasmic unit 

 (see p. 86 et seq. for origin of the term). 



CELLULOSE, the substance of which vegetable cell walls are usually 

 composed ; a carbohydrate. 



CENTROSOME (Gr. KeVr/aoz/, centre ; <ro>/*a, body), a minute proto- 

 plasmic body concerned in the mechanism of nuclear division. 



CENTROSPHERE (Gr. Ktvrpov, centre ; a-tyaipa, sphere), a minute 

 differentiated mass of protoplasm immediately surrounding 

 the centrosome (q.v.). 



CERCARIA (Gr. K>KOS, tail), the tailed larva of a parasitic 

 fluke. 



CHELA (Gr. X'jMj claw), a claw-shaped siliceous spicule found in 

 certain sponges. 



CHEMOTAXIS (Gr. raft?, arrangement), a movement or arrange- 

 ment in response to a chemical stimulus. 



CHLOROPHYLL (Gr. x\a>p6s, green ; <f>v\\ov, leaf), the characteristic 

 green colouring matter of plants. 



CHLOROPLASTIDS (Gr. x^P'^, green ; TrAaorr??, modeller), proteid 

 bodies (contained within cells) in which chlorophyll is 

 deposited. 



CHORDATE (Gr. xP 8 ^ cord), provided with a notochord (q.r.). 



CHROMATIN (Gr. xP^ a > colour), a constituent of the nucleus 

 which becomes stained by certain dyes and which is sup- 

 posed by many to be tho bearer of inheritable tendencies. 



