GLOSSARY 433 



CHLORENCHYMA. The chlorophyll-bearing tissue of plants. 

 CHLOROPHYLL. The characteristic green coloring matter of plants 



through which photosynthesis takes place. 

 CHLOROPLASTID. The special protoplasmic bodies in which 



chlorophyll, or functionally similar pigments, resides. 

 CHORD ATE. An animal whose primary axial skeleton consists tem- 

 porarily or permanently of a notochord. All Vertebrates are 

 Chordates. 

 CHROMATIN. A deeply staining substance characteristic of the 



nucleus, forming chromosomes, etc. See Germ Plasm. 

 CHROMOMERE. A chromatin granule of the linear series which con- 

 stitute a chromosome. 

 CHROMOSOME. One of the deeply staining bodies into which the 



chromatic network of the nucleus becomes visibly resolved 



during mitosis. See Germ Plasm. 

 CILIA. Delicate protoplasmic projections from a cell, which lash 



in unison and propel the cell in the water (e.g., Paramecium), or 



move particles over the cell surface (e.g., cells lining various tubes 



in multicellular forms) . 

 CLASS. In classification, a main subdivision of a phylum. See 



Order. 

 CLEAVAGE. The divisions which transform the egg into the blastula 



stage during development. 

 CLOACA. A cavity at the posterior end of the Vertebrate body, into 



which the intestine, urinary, and reproductive ducts open. Not 



present in most Mammals. 

 COCHLEA. The portion of the ear, in communication with the sac- 



culus, which is the essential organ of hearing ill the higher 



Vertebrates. 

 COELOM. The body cavity, lying between the digestive tract and 



the body wall. Lined with mesodermal tissue. 

 COELOMATE. Possessing a coelom, or body cavity; as in all the 



chief groups of animals above the Coelenterates. The latter are 



acoelomate. 



COELOMIC EPITHELIUM. See Peritoneum. 

 COLLOID. A state of matter in which a substance is finelv divided 



