GLOSSARY. 80 1 



HEMIPTERA (Gr. hemi; andpteron, wing). An order of Insects in which the 



anterior wings are sometimes "hemelytra." 

 HERMAPHRODITE (Gr. Hermes, Mercury; Aphrodite, Venus). Possessing the 



characters of both sexes combined. 

 HETEROCERA (Gr. heteros, diverse ; kercts, horn). Applied to the Moths 



amongst the Lepidoptem, on account of the great variety of shape in their 



antennae. 

 HETEROCERCAL (Gr. heteros, diverse ; kerkos, tail). Applied to the tail of 



Fishes when it is unsymmetrical, or composed of two unequal lobes. 

 HETEROGANGLIATE (Gr. heteros, diverse; gagglion, a knot). Possessing a 



nervous system in which the ganglia are scattered and unsymmetrical (as 



in the Mollusca, for example). 

 HETEROGENESIS or HETEROGENY (Gr. heteros, diverse ; genesis, origin, birth). 



The production of living beings without pre-existent living beings. Or, the 



supposed production of a living being of one kind from a part or the whole 



of the matter of another living being of a perfectly different kind. 

 HETEROMORPHIC (Gr. heteros; morphe, form). Differing in form and shape. 

 HETEROPHAGI (Gr. heteros, other ; phago, I eat). Applied to Birds the young 



of which are born in a helpless condition, and require to be fed by the 



parents for a longer or shorter period. 

 HETEROPODA (Gr. heteros, diverse ; podes, feet). An aberrant group of the 



Gasteropods, in which the foot is modified so as to form a swimming 



organ. 

 HEXAPOD (Gr. hexa, six ; pous, foot). Possessing six legs ; applied to the 



Jnsecta. 

 HILUM (Lat. hilum, a little thing). A small aperture (as in the gemmules of 



sponges), or a small depression (as in floctiluca). 

 HIRUDINEA (Lat. hirudo, a horse-leech). The order of Annelida comprising 



the Leeches. 

 HISTOLOGY (Gr. histos. a web ; logos, a discourse). The study of the tissues, 



more especially of the minuter elements of the body. 

 HOLOCEPHALI (Gr. holos, whole ; kephale, head). A sub-order of the Elasmo- 



branchii comprising the Chimcerce. 

 HOLOMETABOLIC (Gr. holos, whole ; metabole, change). Applied to Insects 



which undergo a complete metamorphosis. 

 HOLOSTOMATA (Gr. holos, whole ; stoma, mouth). A division of Gasteropodous 



Molluscs, in which the aperture of the shell is rounded, or "entire." 

 HOLOTHUROIDEA (Gr. holothourion ; and eidos, form). An order of Echinoder- 



mata, comprising the Trepangs. 

 HOMOCERCAL (Gr. homos, same ; kerkos, tail). Applied to the tail of Fishes 



when it is symmetrical, or composed of two equal lobes. 

 HOMOGANGLIATE (Gr. homos, like ; gagglion, a knot). Having a nervous sys- 

 tem in which the ganglia are symmetrically arranged (as in the Annulosa, 



for example). 

 HOMOLOGOUS (Gr. homos; and logos, a discourse). Applied to parts which 



are constructed upon the same fundamental plan. 

 HOMOMORPHOUS (Gr. homos ; and morphe, form). Having a similar external 



appearance or form. 



HUMERUS. The bone of the upper arm (brachium) in the Vertebrates. 

 HYALINE (Gr. hualos, crystal). Crystalline or glassy. 

 HYDATIDS (Gr. hudalis, a vesicle). The vesicle containing the larval forms 



(Echinococd) of the tape- worm of the dog. 



HYDRAFORM. Kesembling the common fresh- water polype (Hydra} in form. 

 HYDRANTH (Gr. hudra, water-serpent; and anthos, flower). The "polypite" 



or proper nutritive zooid of the Hydrozoa. 

 HYDROCAULUS (Gr. hudra, a water-serpent ; and kaulos, a stem). The main 



stem of the coenosarc of a Hydrozoon. 

 HYDROCYSTS (Gr. hudra; and kustis, a cyst). Curious processes attached to 



the ccenosarc of the Physophoridce, and termed " feelers " (Fiihler and Taster 



of the Germans. 

 HYDRCECIUM (Gr. hudra; and oikos, a house). The chamber into which the 



coanosarc in many of the Calycaphoridce can be retracted. 



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