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ZOOLOGY. 



HEXAPODOUS. Provided with six 

 feet. 



HYMENOPTERA (Gr. humen, hy- 

 men, or membrane ; pteron, 

 wing). An order of insects with 

 two pairs of membranous wings. 



HYOID (Gr. T, eidos, resemblance). 

 A bone in man named from re- 

 sembling the letter U ; its form 

 being different iu other verte- 

 brates : also called os linguae, 

 from its supporting the tongue. 



IMAGO. The final or fourth, 

 winged and adult state of insects. 



INEQUILATERAL Having the two 

 ends unequal, as in the clam, 

 quohog, and most Lamelli- 

 branch shells. 



INEQUIVALVE. With one valve 

 differing in size or shape from 

 the other, as in the oyster or 

 Brachiopod shells. 



IRRORATED. Freckled ; sprinkled 

 with atoms. 



LAMELLIBRANCHIATA (Lat. la- 

 mella, a leaf or sheet ; bmnchia, 

 gill). A class of mollusks with 

 large leaf -like gills. 



LARVA (Lat. larva, a mask). 

 The second stage of the insect, a 

 caterpillar, grub, or maggot. 



LTJMBAR (Lat. lumbus, a loin). 

 Connected with the loins. 



MONOECIOUS (Gr. monos, single ; 

 oikos, house). With the sexual 

 glands, etc., united in the same 

 individual. 



NEMATOCTST (Gr. nema, a thread ; 

 kustis, a bladder). The nettling, 

 stinging organs or thread-cells 

 or lasso-cells of the jelly-fishes 

 and polyps, etc. 



NEUROPTERA (Gr. neuron, a cord ; 

 pteron, wing). The order of 

 net-veined insects. 



NIDAMENTAL. Referring to a 

 nest, or egg-sac. 



NOTOCHORD (Gr. noton, back ; 

 chorde, a string), or chorda 

 dorsalis. The primitive support 

 of the body of vertebrate embry- 

 os, larval ascidians, and the back- 

 bone of the lancelet and lam- 

 preys. 



DETECTED. Covered ; concealed. 



ODONTOPHORE (Gr. odous, a tooth ; 

 pJiero, I carry). The so-called 

 tongue or lingual ribbon of the 

 higher mollusks. 



(ESOPHAGUS (Gr. oisos, a reed ; 

 phagein, to eat). The gullet. 



OPERCULUM (Lat. operio, to cover). 

 In fishes one or more bones 

 covering the gills ; in Gastropod 

 Mollusks a horny plate or solid 

 limestone mass closing the orifice 

 of shells. 



OPISTHOCO3LOUS (Gr. opisthen, be- 

 hind ; koilos, hollow). Those 

 vertebrates with bodies hollow 

 behind and convex in front. 



ORAL. Related to the mouth. 



ORNITHODELPHIA (Gr. ornis, bird ; 

 delphus, womb). The sub-class 

 of mammals and order Monotre- 

 maia. 



ORTHOPTERA (Gr. orthos, straight, ; 

 pteron, wing). The order of 

 insects with straight narrow fore- 

 wings, as the grasshoppers. 



OSTRACODA (Gr. ostracodes, shelled). 

 A group of shelled Crustacea. 



OTOLITHS (Gr. ous, ear ; lithos, 

 stone). Small bones suspended 

 in the internal ear of fishes, or 

 concretions in the auditory sacs 

 of invertebrates. 



