_Dicynodon_, _36_, _192_; beak, 271; supratemporal fossa, 283; teeth, 273 Didelphia, _43_; general characters, 349 Didelphyidae, _43_, _350_; auditory ossicles, 486; pes, 521; teeth, 423 _Didelphys_, _43_; atlas, 443; teeth, 422 _Didus_, _42_; see Dodo Digitigrade, defined, 358 n. Digits, _26_; see Manus and Pes _Dimetrodon_, _36_; thoracic vertebrae, 276 _Dinichthys_, _34_, _70_ Dinocerata, 364; see Uintatheriidae Dinornithes, _40_, _299_; see Moas Dinosauria, _38_; general characters, 204; humerus, 290; ischium, 291; pectoral girdle, 288; pes, 293; pre-orbital vacuity, 284; ribs, 285; vertebrae, 275 f. Dinotheriidae, _47_ _Dinotherium_, _47_, 365; dental formula, 434; teeth, 345 _Diodon_, _33_; beaks, 111; _D. hystrix_, scales, 105 Diphycercal tail, 60, 116 Diphyodont, defined, 7, 344 _Diplacanthus_, _32_, _64_ Dipneumona, _34_ Dipnoi, _34_; general characters, 69; pelvic fins, 131; skull, 124; spinal column, 113; tail, 116; teeth, 111 Dipodidae, _47_ Diprotodont, 423 Diprotodontia, _43_; characters, 350 Dipteridae, _34_, _70_; cranium, 124; tail, 117; teeth, 111 _Dipus_, _47_; cervical vertebrae, 446; pes, 526 Discoglossidae, _36_ _Discoglossus_, _36_; ribs, 182; vertebrae, 172 Distal, defined, 23 n. Divers, _40_; thoracic vertebrae, 332 _Docidophryne_, _36_; shoulder girdle and sternum, =183= Dodo, _42_; wing, 338 Dog, _48_; arm bones, =407=; anterior limb, 405; atlas and axis, =379=; cranium, 384, =389=, =396=; dentition, =375=; innominate bone, =410=; leg bones, =411=; manus, 408, =413=, 511; pectoral girdle, 404; pelvic girdle, 409; pes, =413=, 414; posterior limb, 412; ribs, 402; second lumbar vertebra, =382=; second thoracic vertebra, =382=; skull, 383, =387=; sternum, =403=, 404; vertebral column, 378 Dogfish, _64_; cranium, 73; exoskeleton, 71; median fins, 79; pectoral girdle and fin, 79; pelvic girdle, 81; pelvic fin, 81; ribs, 73; skull, 73, =75=; vertebral column, 72; visceral skeleton, 77; Spotted and Spiny --, _32_ Dolphin, _45_, _357_; lumbar vertebrae, 448; Gangetic --, _45_, see _Platanista_ Donkey, skull, =431= _Dorcatherium_, _45_; manus, 507 Dorsal vertebra, 16 Dorsal shield, crocodile, 238 Down feathers, 306 _Draco_, _38_; ribs, 286 Dromaeognathous, 335 _Dromaeus_, _40_, _299_; see Emeu