3/8 GLOSSARY. 



Monad. (Gr. /M>vds, a unit.) A minute Infusorian. 



Moners. A class of Protozoans. 



Monodelphia. (Gr. pSvos, single ; 5eA.<J>i5s, womb.) The division in- 

 cluding all the higher orders of Mammalia. 



Monoecious. (Gr. /ioVos, single ; OIKOS, house.) Applied to animals 

 in whom the two sexes are united in one individual. 



Monotremata. (Gr. /xoi/os, single ; rprjjua, an opening.) An order of 

 Mammalia having the intestine and the ducts of the urinary and 

 genital organs open into a common cloaca. 



Myriapoda. (Gr. /u,upfos, ten thousand ; irovs, a foot.) A class of Ar- 

 thropoda. 



Natatores. (Lat. nare, to swim.) An order of birds. 



Nectocalyx. (Gr. j>VJx&>, I swim ; Kd\vx, a cup.) The swimming- 

 bell of a jelly-fish. 



Nematocyst. (Gr. %*, a thread ; /flJtrris, a bladder.) The stinging 

 organs or thread-cells of Coelenterata. 



Neuroptera. (Gr. vevpov, a cord ; vrfp6v, a v/ing.) An order of in- 

 sects. 



Noctiluca. A giant monad. 



Notochord (Gr. V&TOV, back ; xP^, a string), or chordad orsalis. 

 A primitive backbone. 



Nudibranchiata. An order of Gasteropoda. 



Octopoda. (Gr. oterd, eight ; irovs, foot.) A group of Cephalopoda. 



Odontophore. (Gr. o5ous, a tooth ; <t>tpti>, I carry.) The lingual rib- 

 bon, or tooth-bearer, of the higher Mollusca. 



(Esophagus. (Gr. ourds, a reed ; ^eryeti/, to eat.) The gullet. 



Operculum. (Lat. operio> to cover.) The bony covering of the gills 

 of fishes ; the horny foot of univalves. 



Ophiura. An order of Echinodermata. 



Opisthoccelous. (Gr. oiriaQe, behind ; KOI'AOS, hollow.) Vertebras 

 with bodies convex in front and hollow behind. 



Ornithodelphia. (Gr. opvis, a bird ; SeXQvs, womb.) Sub-class of 

 mammals and order Monotremata. 



Orthoptera. (Gr. cpQ6s, straight ; irrfptv, wing.) An order of in- 

 sects. 



Otoliths. (Gr. ous, ear ; \iOos, stone.) Small calcareous particles 

 found in the auditory sacs of invertebrates. 



Oviparous. (Lat. ovum, an egg ; pario, I bring forth.) Applied to 

 animals which produce eggs instead of living young. 



Ovipositor. (Lat. ovum, an egg ; pono, I place.) In insects an or- 

 gan by which eggs are deposited in wood, etc. 



Ovisac. The bag-like membrane which contains the eggs. 



