5/4 GLOSSARY. 



INFUSORIA (Lat. infusum, an infusion). A class of Protozoa, so called be- 

 cause tbey are often developed in organic infusions. 



INOPERCULATA (Lat. in, without ; operculum, a lid). The division of pul- 

 monate Gasteropoda in which there is no shelly or horny plate (operculum) 

 by which the shell is closed when the animal is withdrawn within it. 



INSECTA (Lat. inseco, I cut into). The class of articulate animals commonly 

 known as Insects. 



INSECTIVORA (Lat. insectum, an insect; voro, I devour). An order of 

 Mammals. 



INSECTIVOROUS. Living upon Insects. 



INSESSORES (Lat. insedeo, I sit upon). The order of the Perching Birds, often 

 called Passer es. 



INTERAMBULACRA. The rows of plates in an Echinoderm which are not per- 

 forated for the emission of the "tube-feet." 



INTERMAXILL^B, or PR^IMAXILL^. The two bones which are situated between 

 the two superior maxillfe in Vertebrata. In man, and some monkeys, the 

 praemaxillae anchylose with the maxillae, so as to be irrecognisable in the 

 adult. 



INVERTEBRATA (Lat. in, without ; vertebra, a bone of the back). Animals 

 without a spinal column or backbone. 



ISCHIUM (Gr. ischion, the hip). One of the bones of the pelvic arch in Verte- 

 brates. 



ISOPODA (Gr. isos, equal ; podes, feet). An order of Crustacea in which the 

 feet are like one another and equal. 



JUGULAR (Lat. jngulum, the throat). Connected with, or placed upon, the 

 throat. Applied to the ventral fins of fishes when they are placed beneath 

 or in advance of the pectorals. 



KAINOZOIC (Gr. Icainos, recent ; zoe, life). The Tertiary period in Geology, 



comprising those formations in which the organic remains approximate 



more or less closely to the existing fauna and flora. 

 KERATODE (Gr. keras, horn ; eidos, form). The horny substance of which the 



skeleton of many sponges is made up. 

 KERATOSA. The division of Sponges in which the skeleton is composed of 



keratode. 



LABIUM (Lat. for lip). Restricted to the lower lip of Articulate animals. 

 LABRUM (Lat. for lip). Restricted to the upper lip of Articulate animals. 

 LABYRINTHODONTIA (Gr. lalmrinthos, a labj'rinth ; odous, tooth). An extinct 



order of Amphibia, so called from the complex microscopic structure of 



the teeth. 

 LACERTILIA (Lat. lacerta, a lizard). An order of Reptilia comprising the 



Lizards and Slow-worms. 



L^GMODIPODA (Gr. laimos, throat ; dis, twice ; podes, feet). An order of Crus- 

 tacea, so called because they have two feet placed far forwards, as it were, 



under the throat. 

 LAMELLIBRANCHIATA (Lat. lamella, a plate ; Gr. braffchia, gill). The class of 



Mollusca, comprising the ordinary bivalves, characterised by the possession 



of lamellar gills. 



LAMELLIROSTRES (Lat. lamella, a plate ; rostrum, beak). The flat-billed Swim- 

 ming Birds (Natatores), such as Ducks, Geese, Swans, &c. 

 LARVA (Lat. a mask). The insect in its first stage after its emergence from 



the egg, when it is usually very different from the adult. 

 LARYNX. The upper part of the windpipe, forming a cavity with appropriate 



muscles and cartilages, situated beneath the hyoid bone, and concerned in 



Mammals in the production of vocal sounds. 

 LENTICULAR (Lat. lens, a bean). Shaped like a biconvex lens. 

 LEPIDODENDRON (Gr. lepis, a scale ; dendron, a tree). A genus of extinct 



plants, so named from the scale-like scars upon the stem left by the falling 



off of the leaves. 



