GLOSSARY. gjg 



Mes-o-stek'nom (Gr. mesoa, intei-mediate ; steriion, the breast-bons). Tbe 

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

 second pair of ribs and the xiphoid cartilage (xipMsternum). 



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

 thorax in Insects. 



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. 



Mbt-a-po'di-um (Gr. meto, aftei-; pous, the foot). The posterior lobe of the 

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

 velops the operculum when this structure is present. 



Me-tas'to-ma (Gr. meta, after; stoma, mouth). The plate which closes the 

 mouth posteriorly in the VrTustacm, 



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

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

 of the higher Vertebrates. 



Mbt-a-tho eax. (Gr. meta, after ; thorax, the chest). The posterior ring of 

 the thorax in Insects. 



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

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



^o'laks (Lat. mola, a raUl). The " grinders " in man, or the teeth in diphyo- 

 dont Mammals which are not preceded by milk-teeth. 



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

 fish proper, the Polyzoa, the Thmicata^ and the Lamp-shells ; so called from 

 the generally soft nature of their bodies. 



Mol-lus-ooi'da {Molhtsca ; Gr. eidos, form). The lower division of the Mol- 

 hisca, comprising the Polyzoa, Tumcata, and JBrachiopoda. 



Mon'ads (Gr. monas, uuity). Microscopical organisms of an extremely simple 

 character, developed in organic infusions. 



Mo-sroo'u-LODs (Gr. monos, single ; Lat. ooulua, eye). Possessed of only one 

 eye. 



MoN-o-DELPH'i-A(Gr.mo»os, single: <f«?p^«s, womb). The division of i&m- 

 malia in which the uterus is smgle. 



Mo-srcE'ci-oira (Gr. monos, single ; oikos, house). Applied to individuals in 

 which the sexes are united. 



Mou-o-my'a-ky (Gr. monos, single ; mus, muscle). Applied to those bivalves 

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



Mon-o-pht'o-dont (Gr. manos; phni), 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. monos ; and thalamos, chamber). Possessing only a 

 single chamber. . Applied to the shells of Foraminifera and MoUusoa. 



Moir-o-TEEJi'A-TA (Gr. monos ; trema, aperture). The order of Mammals com- 

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

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



Mdl-ti-loo'u-lak (Lat. multi, many ; loculus, a little purse). Divided into 

 many chambers. 



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



MuL-TUN'ec-LA (Lat. multi, many ; ungula, hoof). The division of Perisso- 

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



Mt'e-low (Gr. muelos, marrow). The spinal cord of Vertebrates. 



Myb-i-ap'o-da (Gr. murioi, ten thousand -.podes, feet). A class of Arthropoda 

 comprising the Centipedes and their allies, characterized by their numerous 

 feet. 



Na'cke-otts (Fr. naere, mother-of-pearl, originally Oriental). Pearly ; of the 



texture of mother-of-pearl. 

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

 Na'ta-to-bt (Lat. nare, to swim;. Formed for swimming. 



