COLORADO BEETLE. [ 194 ] 



COLPODA. 



Char. Skeleton consisting of simple sphe- 

 rical roundish or polyhedral fenestrated 

 shells, smooth or spinous, each of which 

 surrounds one of the combined central 

 capsules. 



C. Huxleyi ( Thalassicolla pundata, pt.) . 

 Shell smooth; diam. 250"' In various seas. 



C. spinosa. Shell spinous. Lessina. 



BIBL. Haeckel, Radiolar. 633 ; Huxley, 

 Ann. N. H. 1851, viii. 434, pi. 16. fig. 6. 



COLORADO BEETLE. See DORY- 



PHORA. 



COLOSTRUM. The first liquid se- 

 creted by the mammary glands. See 

 MILK. 



COLOUR. See INTRODUCTION, p. xxxiv. 



COLOURING MATTER, OF ANIMALS. 

 See PIGMENT. 



COLOURING MATTERS, of PLANTS. 

 The green colour of vegetables depends 

 upon the presence of CHLOROPHYLL, and 

 is spoken of under that head. The red and 

 yellow colours assumed by leaves and her- 

 baceous shoots in autumn depend upon a 

 chemical metamorphosis of the chlorophyll, 

 or on its absorption and the discoloration of 

 the cellular tissue. The colours of red 

 cabbage, copper beech and similar plants, 

 depend upon the existence of a colouring 

 liquid in the usually colourless epidermal 

 cells, obscuring the chlorophyll which lies 

 beneath. The red colour presented by many 

 of the lower Algae, such as some of the 

 Palinellacese, appears also to depend upon a 

 metamorphosis of the chlorophyll, con- 

 nected with the vital processes ; it is met 

 with also in the contents of the resting- 

 spores of many of the filamentous Confer- 

 voids. The protoplasm assumes a reddish 

 colour in the pmictum vegetationis of the 

 buds of Monocotyledons in the autumn, 

 which probably depends upon a similar 

 cause. The bright colours of flowers and 

 other parts of the inflorescence of plants, as 

 also of the lower surface of many leaves 

 (Begonia, Victoria, &c.) and herbaceous 

 shoots, arise from the presence of matters 

 of a different kind, almost always dissolved 

 in the watery cell-sap. The colour of petals 

 is ordinarily found to depend upon a cer- 

 tain number of the cells subjacent to the epi- 

 dermal layer being filled with a coloured 

 fluid ; and the depth of the colour is pro- 

 portionate to the number of superimposed 

 layers of such cells, which act like so many 

 layers of a pigment. Each cell is usually 

 filled with one colour when fully deve- 

 loped ; but adjacent cells are often seen, 



in Vciriegated petals, to contain distinct 

 colours, the line of demarcation being accu- 

 rately fixed by the cell-walls, through which 

 the colours do not transude, unless the cells 

 are injured by pressure. In young tissues 

 the colour often has a granular appearance 

 in the cells ; but this is a deception arising 

 from the mode in which the colour is deve- 

 loped. The colourless protoplasm originally 

 filling the cells becomes excavated, as it 

 were, by water-bubbles, and the watery 

 contents of the excavations become co- 

 loured ; they gradually enlarge as the pro- 

 toplasm applies itself more completely to 

 the walls of the cell, until they become 

 confluent and the coloured liquid fills the 

 whole cell-cavity. The isolation of the 

 coloured juice in each particular cell seems 

 to depend upon the primordial utricle or 

 parietal layer of protoplasm ; when this is 

 injured by pressure, or other external cause 

 endosmose is soon set up and the integrity 

 of the cell destroyed. 



In some cases the liquid colouring-matters 

 of flowers have been found to contain solid 

 corpuscles : the red colour-cells of Salvia 

 splendens, and the blue ones of Strelifzia 

 regina, contain globules j and according to 

 Mohl, this is still more commonly the case 

 with the yellow colours : in the yellow 

 perigonial leaves of Strelitzia regina the 

 yellow colour is said to depend upon the 

 presence of crescentic and curled filaments 

 floating in the cell-sap. 



The white patches upon variegated and 

 spotted leaves, such as those of Awnlcr, 

 Holly, variegated Mint, Begonia ari/yro- 

 stigma, &c., arise from the absence of chlo- 

 rophyll in the cells subjacent to the epi- 

 dermis at those parts, which producos the 

 same effects as we see in leaves mined by 

 caterpillars. 



BIBL. Von Mohl, Verm. Schrift. 575. 



COLPID'IUM, Stein, = Paramecfum M- 

 poda, Ehr. & Cl. & Lachmann (Kent, In/us. 

 537). 



COLPOCEPH'ALCJM. Asubgenus of 

 Liothenm (ANOPLURA). 



C. longicaudwn, and four other species ; 

 found on pigeons. 



BIBL. Megnin, Parasites, 91 (fig.). 



COLPO'DA, Schrauk, Ehr. A genus of 

 Holotrichous Infusoria, of the family Col- 

 podea, Ehr., Colpodina, Cl. & L. 



Char. No eye-spot; body sinuous or 

 notched on one side, sometimes renifonn, 

 surface reticulated or marked with nodular 

 obliquely interlacing striae j mouth lateral, 



