Choanoflagellata
56
Choanoflagellata (syn. Choanomastigota) class of the phylum Zoomastigina
(kingdom Protoctista). They are heterotrophic flagellates with a collar of tentacles and an organic or siliceous structure around the cell. Most species are
marine and planktonic.
Chondrichthyes (cartilaginous fishlike shark and rays) class of the Vertebrata. Mostly
marine fish (-7Pisces) with a cartilaginous internal skeleton, which can be calcified but is never ossified. There is no fused skull in the head, and the upper
jaws are independent of the brain case. The backbone runs to almost the end
of the powerful tail fin. There are generally five to seven gill slits on each side
behind the head; the skin is covered with sharp, partly embedded tooth-like
scales (the dermal denticles). The mouth is ventral and the teeth are enlarged
dermal denticles and are not fused to the jaws. A gas-bladder is absent. The fertilization is internal, and for this purpose the males have prominent copulatory organs (claspers) on the inner side of the pelvic fins. They are viviparous or
have leathery eggs. All existing sharks and rays belong to one Chondrichthyes
subclass, the Elasmobranchii (syn. Euselachii). Examples: Squalus and Carcharias
(sharks), Squatina (monkfish), Raja, Torpedo and Dasyatis (rays). The other subclass with living members is the Holocephalii (rabbitfish). They have only one
pair of gill openings, and a long tapering tail (e.g., Chimaera).
Chordata (chordates) phylum of the animal kingdom containing the subphyla
Urochordata (tunicates), Cephalochordata (lancelets) and Vertebrata. These share
three important characteristics: (a) a notochord running from head to tail in
the back of the animal, at least during the embryonic stage; (b) during some
developmental stage, gill slits (lateral openings from the pharynx to the external) and (c) a hollow dorsal nerve cord.
chromatophore (1) cell with pigment granules in its cytoplasm. Rapidly changing disposition (concentration or dispersion) of the pigment within these
cell alters the color of the animal; (2) chromoplast, a plastid (protoplasmic
inclusion) carrying one or several pigments, either carotenoids or chlorophyll. In
the latter case the plastid is called chloroplast.
chromoplast -7chromatophore.
chronostratigraphy (syn. time stratigraphy) branch of stratigraphy that deals
with the age of strata and their time relations. -7stratigraphic hierarchy and
stratigraphy.
Chrysomonadida -7Chrysophyta.
Chrysophyceae -7Chrysophyta.
56
Choanoflagellata (syn. Choanomastigota) class of the phylum Zoomastigina
(kingdom Protoctista). They are heterotrophic flagellates with a collar of tentacles and an organic or siliceous structure around the cell. Most species are
marine and planktonic.
Chondrichthyes (cartilaginous fishlike shark and rays) class of the Vertebrata. Mostly
marine fish (-7Pisces) with a cartilaginous internal skeleton, which can be calcified but is never ossified. There is no fused skull in the head, and the upper
jaws are independent of the brain case. The backbone runs to almost the end
of the powerful tail fin. There are generally five to seven gill slits on each side
behind the head; the skin is covered with sharp, partly embedded tooth-like
scales (the dermal denticles). The mouth is ventral and the teeth are enlarged
dermal denticles and are not fused to the jaws. A gas-bladder is absent. The fertilization is internal, and for this purpose the males have prominent copulatory organs (claspers) on the inner side of the pelvic fins. They are viviparous or
have leathery eggs. All existing sharks and rays belong to one Chondrichthyes
subclass, the Elasmobranchii (syn. Euselachii). Examples: Squalus and Carcharias
(sharks), Squatina (monkfish), Raja, Torpedo and Dasyatis (rays). The other subclass with living members is the Holocephalii (rabbitfish). They have only one
pair of gill openings, and a long tapering tail (e.g., Chimaera).
Chordata (chordates) phylum of the animal kingdom containing the subphyla
Urochordata (tunicates), Cephalochordata (lancelets) and Vertebrata. These share
three important characteristics: (a) a notochord running from head to tail in
the back of the animal, at least during the embryonic stage; (b) during some
developmental stage, gill slits (lateral openings from the pharynx to the external) and (c) a hollow dorsal nerve cord.
chromatophore (1) cell with pigment granules in its cytoplasm. Rapidly changing disposition (concentration or dispersion) of the pigment within these
cell alters the color of the animal; (2) chromoplast, a plastid (protoplasmic
inclusion) carrying one or several pigments, either carotenoids or chlorophyll. In
the latter case the plastid is called chloroplast.
chromoplast -7chromatophore.
chronostratigraphy (syn. time stratigraphy) branch of stratigraphy that deals
with the age of strata and their time relations. -7stratigraphic hierarchy and
stratigraphy.
Chrysomonadida -7Chrysophyta.
Chrysophyceae -7Chrysophyta.