Appendix 835 



Haversian canal (ha -vur' shan) (after Havers, an English physician of the Seven- 

 teenth Century), small canals in bone to conduct blood, etc. 



Heliotropism (he li -ot' ro pizm) (Gr. helios, sun; trope, to turn), response to light. 



Helminthology (hel min -thol' o ji) (Gr. helmins, worm; logos, study), study of 

 worms. 



Hemiptera (he -mip' tur a) (Gr. hemi, half; ptera, wings), order of insects whose 

 front wings have their basal region hardened, while the tips are mem- 

 branous, as in true bugs, 



Hemocoel (he'mosel) (Gr. haima, blood; koilos, hollow), special portion of the 

 coelom for blood circulation. 



Hemoglobin (he mo -glo' bin) (Gr. haima, blood; L. globus, globe), reddish, oxy- 

 gen-carrying substance of red blood corpuscles. 



Hemophilia (hemo-fil'ia) (Gr. haima, blood; philos, loving), a disease, usually 

 hereditary, with a tendency to excessive bleeding, even from slight wounds. 



Hemorrhage (hem'orij) (Gr. haima, blood; rhegnymi, break), loss of blood from 

 broken blood vessel. 



Hepatic (he -pat' ik) (Gr. he par, liver), pertaining to the liver. 



Hepatic portal system, the double blood supply of the liver of vertebrates. 



Herbaceous (hur -ba' shus) (L. herbaceous, grassy), plants without woody tissues. 



Herbivorous (hur -biv' o rus) (L. herba, plant; vorare, to devour), plant-eating 

 organisms (contrast with Carnivorous). 



Heredity (he -red' i ti) (L. hereditas, heir), transmission of physical and mental 

 traits from parent or other ancestor to offspring {see Genetics). 



Hermaphrodite (hur-maf ro dit) (Gr. Hermes and Aphrodite) , having both male 

 and female reproductive organs in one individual (same as Monecious; 

 (contrast with Diecious). 



Heterauxin (het er -ox' in) (Gr. hetero, different; auximos, promote growth), a 

 special hormone which affects plant growth. 



Heterocyst (het' ero sist) (Gr. heteros, different; kystis, sac), clear cell in certain 

 algae which separate the filament into hormogonia. 



Heterogamy (anisogamy) (het er -og' a mi) (Gr. heteros, other; gamos, mar- 

 riage), union of unlike gametes (sex cells) (contrast with Isogamy). 



Heteronomous segmentation (het er -on' o mus) (Gr. heteros, different), dissimilar 

 segmentation or metamerism, such as in crayfish, etc. (contrast with 

 Homonomous). 



Heterosis (het er -o' sis) (Gr. heteros, other), increased vigor due to crossing or 

 hybridization. 



Heterospory (het er -os' po ri) (Gr. heteros, different; spora, spores), production 

 of unlike spores (contrast with Homospory). 



Heterotrophic (het er o -trof ik) (Gr. heteros, different; trophe, food), organisms, 

 unable to manufacture their food; hence they are parasites or saprophytes 

 (contrast with Autotrophic). 



Heterozygote (het er o -zi' got) (Gr. heteros, unlike; zygon, yoke), formed by 

 union of gametes that are unlike in their gene content (contrast with 

 Homozygote). 



Hibernate (hi' ber nat) (L. hiberna, winter), torpor or dormancy of certain 

 organisms due to cold. 



