674 GLOSSARY. 



HE3IELTTKA. (Gr. hemisu, half ; elytron^ a sheath.) A wing, of which one half is 



opaque and firm like an elytrum. 

 Hemiptera. (Gr. hemisu, half ; ptero?i, a wing.) The order of insects in which 



the anterior wings are heraelytra. 

 Hepatic. (Lat. hepar, liver.) Belonging to the liver. 

 Herbivorous. (Lat. herba, grass ; voro, I devour.) The animals which subsist 



on grass. 

 Hersiapiirodite. {Hermes, Mercury ; Aphrodita, Venus.) An individual in 



which male and female characteristics are combined. 

 Heterogaagliate. (Gr. Aete/-os, diverse ; gagglion.) The animals with the gan- 

 glionic ncrA'ous system, and the ganglions scattered, often unsymmetrically. 

 Heteromorphous. (Gr. heteros, another ; viorphe, form.) Of an irregular or 



unusual form, applied to the larvae of certain insects which differ in form from 



the imago, and applicable to the true larval state of all insects. 

 Hexapod. (Gr. hexa, six ; pons, a foot. ) The animals with six legs, such as true 



insects. 

 Histological. (Gr. histos, a tissue ; logos, discourse.) The doctrine of the tissues 



which enter into the formation of an animal and its different organs. 

 Homogangliate. (Gr. homos, like ; gagglion.) The animals with the ganglionic 



nei'vous system and symmetrical arrangement of the ganglions. 

 Homologue. (Gv. homos ; /o^os, speech.) The same organ in different animals 



under every variety of form and function. 

 HoMOMORPHOUS. (Gr. homos, like ; morphe, form.) Of similar form. 

 HoMOPTERA. (Gr. homos, like ; pteroji, a wing.) The insects in which the four 



wings have a similar structure, but restricted, in its application, to a section of 



Hemiptera. 

 Hyaline. (Gr. hualos, crystal.) The pellucid substance which determines the 



spontaneous fission of cells. 

 Hydatid. (Gr. hudatis, a vesicle.) A bladder of albuminous membrane, con- 

 taining serous fluid ; generally detached ; sometimes with an organised head 



and neck. 

 Hydra. (Gr. hudra, a water-serpent.) The modern generic name of certain 



freshwater Polypes. 

 Hydrieorm. Similarly-formed Polypes to the Hydra. 

 Hydrozoa. (Gr. hudra; zoon, animal.) The class of Polvpi organised like the 



Hydra. 

 Hymenoptera. (Gr. /iw/wen, a membrane ; pteron, awing.) The order of insects 



including the bee, wasp, &c. which have four membranous wings. 



Imbricated. (Lat. iinbricatus, tiled.) Scales which lie one upon another like 

 tiles. 



Ingluvies. a crop or partial dilatation of the cesophagus. 



Inopercttlar. Univalve shells Avhich have no operculum or lid. 



Instrumenta Cibaria. (Lat. cibus, food.) The parts of the mouth in insects 

 concerned in the acquisition and preparation of the food. 



Interambulacra. The imperforate plates which occupy the intervals of the per- 

 forated ones, or ambulacra, in the shells of the Echinoderms. See Ambulacra. 



Interganglioxic. (Lat. inter, between ; and gagglion.) The nervous chords in 

 the intervals of the ganglions, which they connect together. 



Interstitial. (Lat. interstitium.) Relating to the intervals between parts. 



Intra-uterine. (Lat. m^z-cf, within ; w^erMS, the womb.) That whicli is, or takes 

 place, within the womb. 



Intussusception. (Lat. intus, within ; suscipio, I take up.) The act of taking 

 foreign matter into a living being. Also the state of a part of a tube when it is 

 inverted within a contiguous part. 



Invaginated. (Lat. in ; vagina, a sheath.) When a part is contained in another, 

 as in a sheath. 



Intertebrata. (Lat. in, used in composition to signify not, like tin ; vertebra, a 

 bone of the back.) Animals without back -bones. 



IsocYCLOus. (Gr. isos, equal ; kuklos, a ring.) An animal composed of a succes- 

 sion of equal rings. 



