HYP- 



143 



HYP- 



The basal portion of any leaf, in- 

 cluding the stalk (dot.). 



hypoptilum (hlpop'tllum) n. [Gk. 

 hypo, under ; ptilon, down.] The 

 after-shaft (zool.}. 



hypopygium (hl'pdplg'mm, hfpopi'- 

 jmm) n. [Gk. hypo, under ; pyge, 

 buttocks.] The clasping organ of 

 a male dipterous insect (zool.}. 



hyporachis (hi'pora'kis) . [Gk. hypo, 

 under ; rhachis, spine.] The stem 

 of the after-shaft of a feather 

 (zool.}. 



hyporhachis, see hyporachis. 



hyposkeletal (hrposkel'Stal) a. [Gk. 

 hypo, under ; skeletos, hard.] Lying 

 beneath or internally to the endo- 

 skeleton (zool.}. 



hyposphene (hi'posfen) n. [Gk. hypo, 

 under ; sphen, wedge.] A wedge- 

 shaped process on the neural arch 

 of the vertebrae of certain extinct 

 reptiles which fits into the hypan- 

 trum (pal.}. 



hypostereom (hl'posteYeom) . [Gk. 

 hypo, under ; stereos, solid.] The 

 third or inner layer of the thecal 

 plates of a Cyst id ; the inner layer 

 of the integument of a Crinoid 

 (zool.}. 



hypostoma (hi'posto'ma) n. [Gk. 

 hypo, under ; sfoma, mouth.] The 

 fold bounding the posterior margin 

 of the oral aperture in Crustacea ; 

 the oral projection or manubrium 

 of a Hydrozoan (zool.}. 



hypostomatous (hfpostom'atus) a. 

 [Gk. hypo, under ; stoma, mouth.] 

 Having the mouth placed on the 

 lower or ventral side (zool.}. 



hypostome, see hypostoma. 



hypotarsus (hl'potar'sus) n. [Gk. 

 hypo, under ; tarsus, ankle.] The 

 " calcaneum " of a bird (zool.}. 



hypothalamus(hl'potharamus). [Gk. 

 hypo, under; thalamos, chamber.] 

 The subthalamic tegmental region 

 and the structures forming the 

 greater part of the floor of the 

 third ventricle (anat.}. 



hypothallus (hl'pothal'us) n. [Gk. 

 hypo, under ; thallus, flattened 

 plate.] The marginal hyphal out- 

 growth ; a membranous case bear- 

 ing sporangia (bot.}. 



hypothecium (hl'pothe'sTum, -shlum) 

 . [Gk. hypo, under ; theke, cup.] 



The layer of dense hyphal threads 

 below the thecium in Lichens ; the 

 upper layer of the ascoma (bot.}. 



hypothenar (hi'pothe'nar) a. [Gk. 

 hypo, under ; thenar, palm of the 

 hand.] Pert, the prominent part 

 of the palm of the hand above the 

 base of the little finger (anat.}. 



hypothetical units, the ultimate 

 component parts of protoplasm ; 

 ultracellular units ranking between 

 the molecule and the cell ; also 

 called variously, physiological units, 

 pangens, gemmules, biophores, 

 bioblasts, somacules, idiosomes, pla- 

 somes, micellae, plastidules, inotag- 

 mata, idioblasts, biogens, gemmae, 

 and microzymas (biol.}. 



hypotonic (hfpotSn'ik) a. [Gk. hypo, 

 under ; tonos, tension.] Appl. a 

 solution whose osmotic pressure is 

 less than that of serum (phys.}. 



hypotrichous (hlpot'rlkus) a. [Gk. 

 hypo, under ; thrtx, hair.] Pert. 

 Infusorians in which the cilia are 

 mainly restricted to the under sur- 

 face, and often form strong seta- 

 like structures (zool.}. 



hypotrochanteric (hl'potrok'anteVik) 

 a. [Gk. hypo, under ; trochanter, 

 runner.] Beneath the trochanter 

 (anat.}. 



hypotympanic (hr'potlm'panik) a. 

 [Gk. hypo, under ; L. tympanum, 

 drum.] Situated below the tym- 

 panum ; pert, the quadrate (anat.}. 



hypoxanthin (hfpozan'thln) n. [Gk. 

 hypo, under ; xanthos, yellow. J A 

 crystalline nitrogenous substance 

 found in muscle tissue and in some 

 seeds (phys.}. 



hypozygal (hfpozl'gal) n. [Gk. hypo, 

 under ; zygon, yoke.] The lower 

 ossicle of a syzygial pair bearing no 

 pinnule (zool.}. 



hypselodont (hlp'selodont) a. [Gk. 

 hypsi, high ; odous, tooth.] Hypso- 

 dont. 



hypsodont (hlp'sodont) a. [Gk. 

 hypsos, height ; odous, tooth.] Pert. 

 or designating teeth with high 

 crowns and short roots (zool.}. 



hypsophyll (hip'sofll) n. [Gk. hypsi, 

 high ; phyllon, leaf.] Any leaf 

 beneath the sporophylls (bot.}. 



hypural (hlp'ural) a. [Gk. hypo, 

 under ; oura, tail.] Pert, a bony 



