226 



GLOSSARY. 



COCCYX (Gr. /tokiy.v, a cuckoo). The terminal 

 portion of the vertebral column in man, so called from 

 its resemblance to a cuckoo's beak. See fig. 32. 



Fig. 15. — Skeleton of Bafs Wing, with outtine 

 of extended membrane. I.-V. The digits as num- 

 bered, ci. Clavicle; r. Radius. 



COLON (Gr.). The middle section of the large 

 intestine, forming the largest portion of the whole in- 

 testine. 



CONDYLE (Gr. kondylos, a knuckle). A rounded 

 knob at the end of a bone serving to form a joint with 

 another bone. 



CORACOID (Gr. korax, a crow, and eidos, form). A 

 bone present in the monotremes (as well as in birds and 

 some other vertebrates) passing 

 from the shoulder-joint to the 

 breast-bone; so called because 

 it corresponds to a process of 

 the shoulder-blade in man re- 

 sembling a crow's beak. See 

 fig. 16. 



CORONOID (Gr. koronc, a 

 crow, and eidos, form). A term 

 applied to the upper anterior 

 process near the hinder end of 

 the lower jaw; so called on ac- 

 count of its curved shape resembling a crow's beak, 

 figs- 33. 36, and 39. 



CORPORA QUADRIGEMINA (Lat., fourfold 

 bodies). A portion of the brain lying between the cere- 

 brum and the cerebellum. 



CORPUS CALLOSUM (Lat., hard or callous body). 

 In anatomy, the great band of brain tissue which unites 

 the two hemispheres of the cerebrum in mammals. See 

 fig. 13. 



CRANIAL REGION. See under Skull. 



CRANIUM (Lat.). The part of the skull inclosing 

 the brain. 



CRUMEN GLANDS. Scent-glands in the deer 

 family, situated in depressions in the lachrymal bone in 

 the neighbourhood of the eye. 



CRUPPER. The rump or buttocks of a horse. 



CUSP (of a tooth). One of the prominences of the 

 molar or cheek-teeth. 



DECIDUATK (I>at. decide, to faU off). A term applied 



Fig. 16.— Part of the Skeleton 

 of the Duck-mole. cr. Cor.icoid. 



See 



to a placenta, the whole of which, including the part 

 formed from the wall of the uterus of the mother, is cast 

 off at the birth of the young animal. 



DECIDUOUS (Lat. decide, to fall off). Liable to be 

 shed; as the milk-teeth. — Deciduous Placenta: same as 

 Deciduate Placenta. 



DEGRADED. In evolutionary language, applied to 

 a structure which is believed to have lost certain special 

 characters possessed by ancestral types. The degraded 

 carnassial of the bears, for example, is a tooth which 

 does not possess the marked characters found in the 

 carnassial teeth of most Carnivora. 



DENTITION (Lit. dens, a tooth), i. The arrange- 

 ment and structure of the teeth. 2. A set of teeth of a 

 particular character. — Complete dentition, a set of teeth in 

 which all the three kinds, incisors, canines, and cheek-teeth 

 (molars and jiremolars) are represented. See fig. 9. 



DEVELOPMENT. A term used in botany and 

 zoology in a special sense to signify the organic changes 

 which take place in animal and vegetable bodies from 

 their embryo state to the state of maturity. 



DIASTEMA (Gr., an interval). Specifically, a gap or 

 interval between teeth. 



DIFFERENTIATE. To render different; specifically, 

 in evolutionary language, to become differentiated is to 

 be made different from a previous type through the 

 acquisition of special characters. 



DIFFERENTIATION, i. The process of differ- 

 entiating. 2. A character or set of characters by which 

 one form is distinguished from another of more primitive 

 type. 



DIFFUSE. As applied to the placenta, having tufts 

 or lobes containing blood-vessels distributed all over the 

 surface of the embryo. 



DIGIT (Lat. digitus, a finger). A general term used 

 by naturalists to denote either fingers or toes in man or 

 the members corresponding to these in 

 the lower animals. The digits are always 

 numbered from the innermost outwards, 

 supposing the palm of the hand or sole 

 of the foot to be laid down flat. Thus 

 the thumb or great-toe is always the first 

 digit; and when certain digits are 

 wanting, as in the horse or cow, 

 the absent digits are always taken 

 into account in naming those which 

 are present. See figs. 17, 

 20-23, 27, 34, and 35. 



DIGITIGRADE (Lat. 

 digitus, a finger, and gra- 

 dior, to step or walk). 

 Applied to animals which 

 in walking touch the 

 ground only with the digits 

 or toes, and not with the 

 parts corresponding to the 

 sole of the foot or jialm of the hand in man; in a more 

 special sense, applied to a group of the Carnivora dis- 

 tinguished by that mode of standing and walking. See 

 fig. 17. 



DILUVIUM (Lat, a deluge). Specifically, in geology, 

 the earlier deposits of Post-tertiary or Quaternary times. 



c/ 



Fig. 17.— Lower part of the Fore-limb 

 of a Lion, to illustrate the digitigradc 

 structure, r. Radius ; «. Ulna ; c. Carpal 

 bones ; ;«. Metacarpal bones ; d. Digits. 



