APPENDIX III 365 



CEPHALizATioN (G. kephale) , the tendency of nerve tissues to collect in 

 the anterior part of the body. 



CERCOS (G. kerkos, tail), as suffix in heterocercal, homocercal. 



CERATO (G. keras, horn), as prefix in ceratohyal, etc. 



Ceratodus (G. keras, plus oclous, tooth), an extinct genus of lung fishes 

 (Dipnoi) ; sometimes Neoceratodus. 



cerebellum (L. dim. of cerebrum, brain), the anterior development from 

 the hindbrain. 



CEREBRUM (L. cerebrum, brain), the dorsal growth of the telencephalon; 

 the higher centers of the brain. 



CERVIX (L. neck), a neck-like opening, the cervix of the uterus; as adjec- 

 tive, cervical, applying to neck. 



Cetacea (G. ketos, whale), an order of mammals, including the porpoises 

 and whales. 



Chelonia (G. chelone, tortoise), an order of reptiles; turtles, etc. 



CHiASMA (G. a cross mark), usually in reference to the optic chiasma or 

 crossing of the nerve fibers from the retina. 



Chimeroids (G. chimaira, monster), an order (Holocephali) of elasmo- 

 branch fishes. They are very aberrant relatives of the sharks. 



Chiroptera (G. cheir, hand, plus pteron, wing), an order of flying mam- 

 mals, the bats. 



Chlamydoselache (G. chlamys, a mantle, plus selachos, shark), a genus 

 of primitive, six-gilled sharks from the coast of Japan. 



choana (G. a funnel), the internal and external openings of the nares. 



chondrocranium (G. chondros, cartilage, plus kranion, skull), the car- 

 tilaginous skull of cyclostomes and elasmobranchs; and the embryonic 

 skull of higher embryos, around which the dermal bones are laid 

 down. The chondrocranium ossifies in groups above the Chondrostei. 



chondros (G. cartilage), a combining form; perichondrium; Chondrostei. 



Chondrostei (G. chondros, plus osteon, bone), an order of bony fishes, 

 including the sturgeon and spoon-bill (Polyodon), in which the 

 chondrocranium remains unossified. The most primitive living bony 

 fish. 



CHORDA (L. a cord or string), a combining form; notochord, Chordata. 



Chord.ata (L. chorda), a phylum of animals, including the vertebrates and 

 three other sub-phyla. 



CHORION (G. membrane), the outer embryonic membrane, developed syn- 

 chronously w^ith the amnion; and until fusion is completed, continu- 

 ous with it. 



CHYME (G. juice, fluid), a suffix, as in mesenchyme, referring to embryonic 

 cells before tissue formation has taken place. 



CILIARY (L. cilium, eyelid), near, or associated with, the eye or eyelashes. 



Cladoselache (G. dado, branch or twig, plus selachos, shark), a genus of 

 extinct sharks with fins attached to the body by broad bases; an 

 important link in the fin-fold theory. 



CLAST (G. klao, to break), a suffix as in osteoclast, the bone destroying 

 cells. 



CLITORIS (G. kleio, to close), a structure of the female genitalia, homolo- 

 gous with the urethral body of the penis. 



CLO.^CA (L. cloaca, a sewer), the common opening of the digestive and 

 urinogenital openings; found in many fish and amphibia, reptiles, 

 birds, and monotreme mammals. 



