GLOSSARY. 339 



ME8-o-9TSE'injM (Gr. mesos, intermediate j sternon, the breast-bone). The 

 middle portion of the sternum, intervening between the attachment of the 

 second pair of ribs and the xiphoid cartilage {xipMstemum). 



Mes-o-tho'bax (Gr. mesos ; and thoriM., the chest). The middle ring of the 

 thorax in Insects. 



Mbs-o-zo'io (Gr. mesos ; ao«, life). The Secondary period in Geology. 



Met-a-oak'pus (Gr. meta, after ; harpos, the wrist). The bones which form 

 the " root of the hand," and intervene between the wrist and the iingers. 



Met-a-mob'pho-sis (Gr. meta, implying change ; morphe, shape). The changes 

 of form which certain animals undergo in passmg from their younger to 

 their fully-grown condition. 



Met-a-po'di-um (Gr. mete, after ; po'jie^ the foot). The posterior lobe of the 

 foot in MoUusca; often called the " operculigerous lobe," because it de- 

 velops the operculum when this structure is present. 



Mb-tas'to-ma (Gr. meia, after; a^oma, mouth). The plate which closes the 

 mouth posteriorly in the Crustacea. 



Met-a-tab'sds (Gr. meta, after; tarsos, the instep). The bones which inter- 

 vene between the bones of the ankle {farms) and the digits in the hind-foot 

 of the higher Vertebrates. 



Met-a-tho'rai: (Gr. meia, after; thorax, the chest). The posterior riug oi 

 the thorax in Insects. 



Mi-met'io (Gr. mimetikos, imitative). Applied to organs or animals which 

 resemble each other in external appearance, but not in essential structure. 



Mo'laes (Lat. mola, a mill). The " grinders " in man, or the teeth in diphyo- 

 dont Mammals which are not preceded by milk-teeth. 



MoL-Lus'oA (Lat. mollis, soft). The sub-kingdom which includes the Shell- 

 fish proper, the Folysoa, the TunicatUj and me Lamp-shells ; so called from 

 the generally soft nature of their bodies. 



Mol-lus-ooi'da ^Mbllusoa ; Gr. eidos, form). The lower division of the MoJ- 

 luaca, comprising the Polyzoa, Tunicata, and Brachiopoda, 



Mou'ads (Gr. monaS, unity). Microscopical organisms of an extremely simple 

 character, developed in organic infusions. 



Mo-woo' D-Lons (Gr. Tnonos, smgle ; Lat. ooulus, eye). Possessed of only one 

 eye. 



Mos-o-dblph'i-a (Gr.moTKW, single; <i«ZpA«s, womb). The division of J&m- 

 maUa in which the uterus is smgle. 



Mo-ir(B'oi-ODS (Gr. monos, single ; oikos, house). Applied to individuals in 

 which the sexes are united. 



Mos-o-my'a-ey (Gr. monos, single ; »mMj muscle). Ajiplied to those bivalves 

 {Lamellibranchiata) in which the shell is closed by a single adductor muscle. 



MoN-o-PHt'o-DOKT (Gr. monos : phuo, I generate ; odous, tooth). Applied to 

 those Mammals in which only a single set of teeth is ever developed. 



Mok-o-thal'a-mous (Gr. m,onos ; and thabmios, chamber). Possessing only a 

 single chamber. Applied to the shells of Foranninifera and Molhusca. 



Mon-o^tbbm'a-ta (Gr. monos ; trema, aperture). The order of Mammals com- 

 prising the Duck-mole and Echidna, in which the intestinal canal opens 

 into a°' cloaca " common to the ducts of the urinary and generative organs. 



Mnt-Ti-Loo'n-LAR (Lat. multi, many ; loculus, a little purse). Divided into 

 many chambers. 



Mul'ti-valve. Applied to shells which are composed of many pieces. 



MiiL-Toif'ou-LA (Lat. multi, many ; ungula, hoof). The division of Perisso- 

 dactyle Ungulates, in wliich each foot has more than a single hoof. 



Mt'b-lon (Gr. muelos, marrow). The spinal cord of Vertebrates. 



Mte-i-ap'o-da (Gr. murioi, ten thousand Ixodes, feet). A class of Arihropoda 

 comprising the Centipedes and their allies, characterized by their numerous 

 feet. 



Na'oke-obs (Fr. nacre, mother-of-pearl, originally Oriental). Pearly ; of the 



texture of mother-of-pearl. 

 Nat-a-to'res (Lat. nare, to swim). The order of the Swimming Birds. 

 JNa'ta-to-kv (Lat. nare, to swim). Formed for swimming. 



