358 GLOSSARY. 
Hyor (Gr. U, eidos, form). A bone which supports the tongue, and 
which derives its name from its resemblance in man to the letter U. 
HYRACOIDEA (Gr. hurax, a shrew ; eidos, form). An order of Mammalia. 
ICHTHYOMORPHA (Gr. ichthus, a fish; morphe, shape). An order of Amphi- 
bia, comprising the fish-like Newts, &ce. 
ICHTHYOPHTHIRA (Gr. tchthus, a fish; phtheir, alouse). Anorder of Crustacea, 
IcHTHYOPSIDA (Gr. ichthus, fish ; opsis, appearance). The primary divi- 
sion of the Vertebrata, which includes the two classes of the Amphibia 
and P2sces. 
ICHTHYOPTERYGIA (Gr. ichthus, a fish ; pteruw, a wing). An extinct order 
of Reptiles. 
ICHTHYOSAURIA (Gr. ichthus, a fish ; sawra, a lizard). An extinct order of 
Reptiles. 
Tuaco (Lat. an image or apparition). The perfect insect, after it has 
passed through all its metamorphoses. 
Inctsor (Lat. incido, Icut), The cutting-teeth fixed in the front of the up- 
per jaw, and the corresponding teeth in the lower jaw of the Mammalia. 
INEQUILATERAL. Having the two sides unequal, as is the case with the 
shell of the ordinary bivalves (Lamellibranchiata). 
INEQUIVALVE. Composed of two unequal pieces or valves; as is the case 
with the shells of the Brachiopoda. 
INFUSORIA (Lat. infuswm, an infusion). <A class of Protozoa, so called 
from their frequent occurrence in organic infusions. 
Insucra (Lat. inseco, I cut into), The class of Articulate animals com- 
monly known as Insects. 
INSECTIVORA (Lat. insectum, an insect; voro, I devour). An order of 
Mammalia. 
INsEctIvorovus. Living upon Insects. 
INTERAMBULACRA (Lat. inter, between ; ambulacrum, a place to walk in). 
The rows of plates in an Echinus which,are not perforated for the emis- 
sion of the tube-feet. 
INTUSSUSCEPTION (Lat. intus, within; suscipio, I take up). The act of 
taking foreign matter into a living being. . 
INVERTEBRATA (Lat. in, without ; vertebra, a bone of the back). Animals 
without a spinal column or back-bone. 
Isopopa (Gr, isos, equal ; podes, feet). An order of Crustacea in which 
the feet are equal and like one another. 
LaBIuM (Lat. for lip), Restricted to the lower lip of Articulate animals. 
LaBrvM (Lat. for lip). Restricted to the upper lip in Articulate animals. 
LABYRINTHODONTIA (Gr. laburinthos, a labyrinth ; odous, a tooth). An 
extinct‘order of Amphibia. 
LACERTILIA (Lat, lacerta, a lizard). An order of Reptilia comprising the 
Lizards and Slow-worms. 
L&MODIPODA (Gr. laimos, throat; dis, twice ; podes, feet). An order of 
Crustacea, with two legs under the throat. 
LAMELLIBRANCHIATA (Lat. lamella, a plate; Gr. bragchia, gills), The class 
of Mollusca, comprising the ordinary bivalves with leaf-like gills, 
LARVA (Lat. amask), The insect in its first stage after its emergence 
. from the egg, when it is usually very different from the adult. 
LEPIDOPTERA (Gr. lepis, a scale; pteron, a wing). The order of Insects 
comprising the Butterflies and Moths, characterised by having four 
wings usually covered by minute scales. 
Lrnauat (Lat. lingua, tongue). Connected with the tongue. 
LUCERNARIDA (Lat. lucerna, a lamp). An order of the Hydroza. 
LuMBAR (Lat. dumbus, a loin). Connected with the loins. 
