GLOSSARY. 677 



NoTAL. (Gr. 7iotos, the back.) Belonging to the back. 



Nucleated. Having a nucleus or central particle ; applied to the elementary 

 cells of animal tissues, the most important properties of Avhich reside in the nu- 

 cleus. 



NuDiBRACHiATE. (Lat. nudus, naked ; brachia, arms.) The Polypes, whose arms 

 are not clothed with vibratile cilia. 



NuDiBRANCHiATE, (Lat. nudus, naked; bragchla, gills.) An order of Gastro- 

 pods in which the gills are exposed. 



OcTOPODA. (Gr. octo, eight ; pons, a foot.) Animals with eight feet. The name 



of the tribe of Cephalopods with eight prehensile organs attached to the head. 

 CEsoPHAGDS. The gullet or tube leading from the mouth to the stomach. 

 Olfactory. (Lat. olf actus, the sense of smelling.) Relating to that sense. 

 Onychoteuthis. (Gr. onux, a hook ; teuthis, a calamary.) The genus of Cala- 



maries armed with hooks or claws. 

 Oolite. (Gr. oon, egg ; lithos, stone.) An extensive group of secondary lime- 

 stones, some of which are composed of rounded particles, like the roe or eggs of a 



fish. 

 Operculum. (From the Latin for lid. ) Applied to the horny or shelly plate 



which closes certain univalve shells ; also to the covering of the gills in fish, and 



to the lids of certain eggs. 

 Oral, (Lat. os, the month.) Belonging to the mouth or to speech. 

 Orthocera and Orthoceratite. ( Gr. orthos, straight ; keras, horn.) The extinct 



Cephalopods which inhabited long conical chambered shells like a straight horn. 

 Ortiioptera. (Gr. orthos, straight ; pteron, a wing. ) The order of insects, with 



elytra and longitudinally folded wings. 

 Osseous. (Lat os, a bone.) Bony. 



Otolithes. (Gr. o?«, an ear ; lithos, a stone.) Tlie stony or chalky bodies be- 

 longing to the internal ear. 

 Ovarium. (Lat. ovum, an egg.) The organ in which the eggs or their elementary 



and essential parts are formed. 

 OvicAPSULE. (Lat. ovum, an egg ; capsula, a bag.) An egg-bag formed by 



some membrane or secretion of the animal. 

 OviGEROUs. (Lat. ovum, an egg ; gero, I bear.) Animals or parts containing or 



supporting eggs. 

 Oviparous. (Lat. ovum; pario, I bring forth.) The animals which bring forth eggs. 

 Ovipositor. (Lat. ovum ; pom, I place.) The organ in insects, which is often 



large and complicated, for the transmission of the eggs, during exclusion, to 



their appropriate place. 

 OvoviviPAROUS. (Lat. ovum, egg ; vivus, alive ; pario, I produce.) The animals 



which produce living young, hatched in the egg within the body of the parent, 



without any connection with the womb. 



Palaeontology. (Gr. palaios, ancient ; onta, beings ; logos, discourse.) The 



history of ancient extinct organised beings. 

 Pallial. (Lat. pallium, a cloak.) Relating to the mantle or cloak of the Mol- 



lusca. 

 Palliobranchiata. (Lat. pallium; bragchia, gills.) The class of acephalous 



Mollusca in which the gills are developed from the mantle. 

 Palpi. (Lat.pa/po, I touch.) The organs of touch developed from the labium 



and maxillffi of insects. 

 Papilla. (Lat. for nipple.) Minute soft prominences generally adapted for 



delicate sensation. 

 Papyraceous. (Gr. papuros_, paper.) Of the consistency of paper. 

 Parenchyma. The soft tissue of organs; generally applied to that of glands. ^ 

 Parietes. (Lat. paries, a wall.) The walls of the dirterent cavities of an animal 



hody. . _ 



Parthenogenesis. (G\\ parthenos, a virgin; gignomai, to be born.) Propagation 



by self-splitting or self-dividing, by budding from without or within, and by any 



mode save by the act of impregnation; the parthcnogcnetic individuals being 



sexless or virgin females. 



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