=Chro´mo-somes= [Gr. _croma_, color: _soma_, body.] Nuclear threads. =Chry´so-thrix= [Gr. _chrysos_, gold; _thrix_, hair.] =Clo-a´ca= [Lat. _cloaca_, a common sewer.] The common cavity into which the digestive, urinary, and genital canals empty in most vertebrates below placentals, and in all mammalian embryos. =Coc´ci= [Gr. _kokkos_, berry.] Pl. of _coccus_. Isolated spherical cells (bacteria). =Co-coons´= [F. _cocon_, dim. of _coque_, shell; < Lat. _concha_, shell.] The protective envelopes spun by certain larval insects, as silkworms, in which they are inclosed in the chrysalis state. =Co-do-si´ga um-bel-la´ta= [Gr. _kodon_, a bell; _sige_, silence; Lat. _umbella_, dim. of _umbra_, shade.] =Cœ-cil´i-a= [Lat. _cæcus_, blind.] Footless amphibians of snake-like form; rudimentary eyes; no neck. =Cœ-len-te-ra´ta= [Gr. _koilos_, hollow; _enteron_, intestine.] =Cœ-len´ter-ate= [Vid. Cœlenterata.] =Cœ´lome= [Gr. _koilos_, hollow.] The body-cavity of a metazoan between the viscera and the body-wall. =Combs= [AS. _camb_, crest or ridge.] The fleshy crests on the heads of roosters, etc. =Con-dy-lar´thra= [Gr. _kondylos_, knuckle; _arthron_, joint.] An Eocene group of ungulates in which the astragalus is not interlocked laterally with the tibia and its head rounded. =Co-nif´e-ræ= [Lat. _conus_, cone; _fero_, bear.] The pine family of trees. =Co´nus ar-te-ri-o´sus= [_Latin phrase_.] The arterial, cone-shaped portion of the left ventricle of the heart. =Co-rol´la= [Lat., dim. of _corona_, crown.] The inner set of leaves of flowers and usually bright-colored. The individual parts are called petals. =Crests= [Lat. _crista_, tuft.] Projecting natural growths on the tops of animals’ heads and usually ornamental, as the cock’s comb, or the lengthened feathers of a bird. =Cre-o-don´ta= [Gr. _kreas_, flesh; _odous_, tooth.] A group of fossil animals containing forms ancestrally related to existing Carnivora. =Cre-ta´ceous= [Lat. _creta_, chalk.] Pertaining to the latter part of the Reptilian age. =Cri-noi´de-a= [Gr. _krinon_, lily; _eidos_, form.] Stone-lilies; stalked star-fishes. A division of Echinoderms. =Cri´noids= [Vid. Crinoidea.] =Croc-o-dil´i-a= [Lat. _crocodilus_, lizard.] An order of reptiles including crocodiles, alligators, and gavials. They are the highest order of reptiles. In them the heart and brain approximate very closely to that of birds. =Cros-sop-te-ryg´i-a= [Gr. _krossoi_, tassels; _pterygion_ dim. of _pteryx_, wing.] A group of fishes with paired, lobate fins, and with an endodermal skeletal, axis fringed with dermal rays. =Crus-ta´ce-a= [Lat. _crusta_, crust.] A division of arthropods containing crabs, lobsters, shrimps, crawfish, barnacles, etc. =Cryp´to-gams= [Gr. _kryptos_, hidden; _gamos_, marriage.] The lower of the two great subdivisions of the plant kingdom. They have no true flowers containing stamens, pistils, and seeds; they propagate by means of spores.