435 



genus of the most minute and| 

 simple microscopic animalcules, j 

 shaped like spherical cells. 



Monocotyledons, plants with a single j 

 seed lobe, 72. 



Monoc'ulus (Gr. IJLOVOQ, single ; Lat. 

 oculusj&n eye), the animals which 

 have but one eye. 



Monomy'ary (Gr. /xorog, single ; 

 Hvov, a muscle), a bivalve whose 

 shell is closed by one adductor 

 muscle. 



Monothal'amous (Gr. /IOVOQ, single; 

 Oa\a/.io, a chamber), a shell 

 forming a single chamber, like 

 that of the whelk. 



Motion, 205 307 ; apparatus of, 

 205 227; locomotion, 228288; 

 standing, and modes of progression, 

 289307. 



Mo'tory, the nerves which control 

 motion. 



Moulting, the shedding of feathers, 

 hair, &c., 412. 



Mul'tivalve (Lat. multus, many ; 

 valva, folding doors). 



Mus'cular tissue, one of the primary 

 forms of animal tissues having 

 the power of contraction, 44, 54. 



Myri'apods (Gr. pvpioQ, ten thou- 

 sand ; 7rouf , foot), the order of 

 insects characterized by their nu- 

 merous feet. 



NA'CREOUS (Fr. nacre), pearly, like 



mother-of-pearl. 

 Natato x res (Lat. nato, I swim), birds 



withwebbedfeetforswimming,xxi. 

 Na'tatory, an animal or part formed 



for swimming. 

 Natural history, extent of the study 



of, 30. 



Nature, ages of, 656 690. 

 Nautilus, cephalopods with cham- 

 bered shells, xxii. 



Nep'tunic,orwater-formedrocks,646. 

 Nerves, structureof the primary fibres 



of, 80, 81; tbeir termination, 82 



119. 



Nerves, pairs of, their several offices, 

 97114. 



Ner'vous system of man, 84 95 ; of 

 other classes of animated beings, 

 92 119; special senses,120 184. 



Nervous system, the, and general 

 sensation, 76 79. 



Ner'vous tissue, 45, 55 ; its structure, 

 80, 81 ; termination, 82. 



Ner'vures (Lat. nervus, a sinew), 

 the delicate frame of the mem- 

 branous wings of insects. 



Neurapoph'yses (Gr. vtvpov, nerve ; 

 aTTopucric, a process of bone), 

 those vertebral elements which 

 enclose and protect the spinal cord 

 and brain. 



Neu'ral- spine, the spinous processes 

 of the vertebra. 



Neuri'lemma (Gr. vtvpov, a nerve ; 

 \i]fip,a, a covering), the mem- 

 brane which surrounds the ner- 

 vous fibre. 



Neurop'tera (Gr. vtvpov, a nerve ; 

 TTTepov, a wing), the order of in- 

 sects with four wings, character- 

 ized by their numerous nervures, 

 like those of the dragon-fly. 



Nodu x le (dim. of nodus, a knot), a 

 little knot-like eminence. 



Nor'mal (Lat. norma, rule), accord- 

 ing to rule, ordinary or natural. 



Notosau'rus, an extinct saurian, 672. 



Nucleated, having a nucleus or cen- 

 tral particle ; applied to the ele- 

 mentary cells of animal tissues, 

 the most important properties of 

 which reside in the nucleus, 38,56. 



Nu v cleus and nu^cleolus, 56 



Nu'dibrachiate (Lat. nudus, naked ; 

 Gr. /3/oay^irt, arms), the polyps, 

 whose arms are not clothed with 

 vibratile cilia. 



Nudibranchiata x (Lat. nudus, naked ; 

 Gr. (3pavx<-a, gills), an order of 

 gasteropods, in which the gills 

 are exposed. 



Nutrition, 308349 , digestion, 312 

 349 



