824 



INDEX. 



Natatorial birds (Lat. natatores 

 swimmers), 150 



Neural arch (Gr. neuron a nerve) of 

 the vertebra), 26 



Neural arches of the skull — the en- 

 cephalic, the mesencephalic, the 

 prosencephalic, and the rhinen- 

 cephalic, 51 



Neural spine of parietal vertebra, 

 called parietal bone, 43 ; of fishes, 

 ib. 



Neurapophysis (Gr. neuron a nerve, 

 and apophysis springing from), a 

 neural process, 27 et scq. sscpe ; 

 of parietal vei'tebra, called ali- 

 sphenoid, 43 



Neurine matter of animals, 13 



Neuro-skeleton, 16, 18; segmental 

 composition of the, 26 



Neuro-skeletal segments of verte- 

 brae of the skull — the occipital, 

 the parietal, the frontal, and the 

 nasal, 51 



Notation of teeth, 813 



Notochord (Gr. notos the back, and 

 chorda cord), the embryonic dor- 

 sal gelatinous chord,' 33 







Occipital vertebra (Lat. occiput the 

 back part of the head), of the 

 cod-fish, 40 ; of the python, 77 



Odontoid process of the axis (Gr. 

 odous a tooth, and eidon resem- 

 blance), 96 



Olfactory capsule (Lat. olfacio to 

 smell, and capsula a little cover- 

 ing), 81 



Olfactory lobes, the, 47 



Operculum (Lat. a covering flap), 

 bones of the, 46 ; consists of four 

 bones, the preopercular, the oper- 

 cular, the subopercular, and the 

 interopercular, ib. 



Ophidia (see Serpent Tribe). 



Opisthocoelian type of vertebrae 

 (Gr. opisthos behind, and koilos 

 concave), 97 



Optic foramina (Gr. optomai to see, 

 and Lat. foramen an opening), 80 



Orbitosphenoid bones (Lat. orUs a 

 circle, Gr. sphen a wedge, and 

 eidos resemblance), 45, 80 



Ornithorhynchus (Gr. ornithos a 

 bird, and rhynchos a beak), teeth 

 of the, 258 



Orycteropus (Gr. orykter a digger, 

 and pous a foot), tooth of the, 238 



Os coccygis (Lat. os a bone, andGr. 

 kokkuz a cuckoo), 215 



Os spheno-occipital of the skull, 218 



Osseous system, primary classifica- 

 tion of the, 16 



Ossicles (Lat. ossiculum a little 

 bone), 120 



Osteine (Gr. osteon a bone), the 

 matter or tissue so called, 13 ; 

 arrangement of, 21 



Osteodentine (Gr. osteon a bone, and 

 Lat. dens a tooth), 233 ; in vari- 

 ous genera of fishes, 247 



Osteology (Gr. osteon and loyos a 

 discourse on bones), principles 

 of, 13 ; general and special terms 

 in, 221 (see Skeleton and 

 Bones). 



Otocrane (Gr. ota the ears, and 

 cranion the skull), 31 



Ourang-outang, skeleton of the, 

 210 ; dentition of the, 302 



Ox, tarsal bones of the, 185 



Pachydermata (Gr. pachus thick, 



and dermaia skins), dentition of 



the, 308 

 Palatine bones or Palatines (Lat. 



palattim the palate), 47 

 Palato-pterygoid process (Lat. pa- 

 latum the palate, and Gr. ptery- 



goidos wing-like), 168 

 Parapophyses (Gr. para transverse, 



and apophysis a process), 27 et 



seq. saspe. 

 Parietal vertebra (Lat. paries a 



wall), 44 

 Paroccipitals (Gr. para from, and 



Lat. occiput back of the head), 132 

 Parrot-fishes, jaws and food of the, 



247 



