138 GLOSSAEY. 



INCISOR (incido, to cut), the teeth (usually broad and sharp) fixed in the prsemuj-illa 



of Mammalia, and those in the lower jaw which shut against them. 

 INCUS (an anvil, fr. incudo), the bone of the ear in Mammalia which, according to 



Reichert, is the homologue of the os quadratum in lower vertebrates, but has 



been now shown to be represented by a ligament only in birds, a cartilnge in 



Sphenodon (Hatteria) and other reptiles, and the hyo-mandibular bone in 



osseous fishes : v. MALLEUS. 

 INFCNDIBULVM (a funnel), the channel formed by folded processes of the mantle 



by winch water passes out from the branchial chamber of Mollusks. 

 INFUSORIA (infusum, fr. in and/undo, pour), a class of microscopic animals, named 



from their occurrence in vegetable infusions. 

 INGUEN, the groin. 

 INSECTA (inseco, to cut in pieces, as in Greek, ivro^o. Arist. H. A. iv. 1, 5 fr. 



evre/jLvu], a class of Arthropodous Annulosa. "Jure omnia Insecta appellata 



ab incisuris, quse nunc cervicuin loco, nunc pecterum atque alvi, prsecincta 



separant membra." Plin. xi. 1, 1. 



INSECTIVORA (insectum, an insect ; voro, eat), an order of Mammalia. 

 INTERMAXILLARY or prse-maxillary bones, so called because they are placed in front 



of and between the maxillse of Vertebrata, with which they unite in adult life 



in Man and some of the apes. 

 ISOPODA (icros, equal ; irovs, foot), an order of Crustacea included under Edrio- 



phthalmia. 



JUGAL (jvgum, a yoke), a bone of the face corresponding to the os malee or cheek- 

 bone in human anatomy, and forming part of the zygoma. 

 LABIUM (a lip), the lower part of the mouth in insects formed of the coalesced 



second part of maxillse. 



LABRUM (form of Idbium), the upper part of the mouth in insects. 

 L^MODIPODA (\aifj.6s, throat ; Si-, two ; irovs, foot), a group of Crustacea with two 



legs under the throat, now included under EdrioplMialmia. 

 LAMELLIBRANCHIATA (lamella, dim. of lamina, a thin plate ; ppdyx'a, gills), an 



order of Mollusca. 

 LARVA (a mask), the name applied by Linnaeus to the grub or caterpillar, which 



is the first stage in the metamorphosis of Insects. 

 LEPIDOPTERA (\etris, scale ; wrtp6v, wing), an order of Insects with wings covered 



with scales. 

 LEPIDOSIREN (\tiris, scale ; ffeip-fiv, a siren applied to one of the Amphibia), a fish 



resembling the Siren, but covered with scales. 



LEPIDOSTEUS (\stris, scale ; bffreov, bone), the Bony Pike of North America. 

 LOPHOPHORE (Ao</>os, a plume ; Qepw, bear), the oral disk of Pohjzoa. 

 LUCERNARIA (lucerna, a lamp), a genus of Hydrozoa. 



MACRATJCHENIA (juawp^s, long ; aux^, neck), an extinct genus of Mammalia. 

 MALACOSTRACA (^aKaKoffrpaKo. Arist., soft-shelled, v. ENTOMOSTRACA), the higher 



Crustacea, so called by Latreille in distinction from the harder-shelled 



Mollusca. 

 MALLEUS (a hammer), a bone of tlie internal ear in Mammalia, which Reichert 



supposed to answer to the pars articularis of the mandible in Sauropsida, but 



which is probably the true homologue of the os quadratum : v. INCUS. 

 MALLOPHAGA (fj.a\\6s, wool ; <j>a.ye1i>, to eat), a group of parasitic Insects. 

 MAMMALIA (mamma, a breast), a class of Vertebrata distinguished by suckling 



their young. 

 MANDIBLE (mandibulum, fr. mando, to chew), in Vertebrata, the lower jaw, answering 



