USED IN NATURAL HISTORY. 



79 



HOMOP'TERA. fr. gr. omos, same ; 

 pteron, wing. An order of in- 

 sects. 



HOMOP'TER^E. Lat. plur. of homop'- 

 tera. 



HOMOP'TERAN. Of the order ho- 

 mop'tera. 



HOMO'RGANA. fr. gr. organon, an or- 

 gan. One of the primary classes 

 of plants, as divided with refer- 

 ence to the rotation, or general 

 motion of the sap. 



HOMOTRO'PAL. fr. gr. trepo, to turn. 

 Having the same direction as the 

 body to which it belongs, but not 

 being straight; applied to the em- 

 bryo of a seed. 



HONEY-DEW. A sweetish substance 

 ejected by aphides on the leaves 

 of plants ; also a substance seen 

 hanging occasionally in drops 

 from the points of leaves of plants. 



HONEY-PORE. The pore in flowers 

 which secretes honey. 



HONEY-SCALES. The scales in flow- 

 ers which secrete honey. 



HONEY-SPOTS. The spots in flowers 

 which secrete honey. 



HOODED. Curved or hollowed at 

 the end into the form of a hood. 



HOR'DEUM. Lat. Barley. 



HORN. Any long subulate process 

 in a flower. 



HO'RNBLENDE. fr. ger. horn; blen- 

 den, to dazzle : having the lustre 

 of horn, jlmphibole. A mineral 

 of dark green or black colour, 

 abounding in oxide of iron, and 

 entering into the composition of 

 several of the trap rocks. There 

 are three varieties; common, horn- 

 bleride-schist, and basaltic horn- 

 blende. 



HORNBLENDE SCHIST. A slaty va- 

 riety of hornblende. 



HO'RRIDA. Lat. Horrid ; spiny. 



HORTULA'NA. Specific name of a 

 bunting. 



HORTUS srccus. Lat. A dry gar- 

 den. Herbarium. 



HU'MERAL CINCTURE. A chain of 

 bones, forming a sort of belt, 



which sustains the pectoral fin, 

 anterior extremity, of fishes. 



HU'MERUS. Lat. Shoulder. Name 

 of the bone placed between the 

 shoulder and elbow. 



HUMMOCK. A circular and elevated 

 mound. A sheet of ice, which 

 presents a surface generally level, 

 but here and there diversified by 

 projections, arising from the ice 

 having been thrown up by some 

 pressure to which it has been sub- 

 jected. 



HU'MULUS. Lat. Hops. 



HU'MUS. Lat. Moist earth. Vege- 

 table earth or mould. 



HUSKS. The dry envelopes of ei- 

 ther flowers or fruits. 



HYAL^'A. fr. gr. ualos, glass. A ge- 

 nus of beautiful pteropods, re- 

 markable for the transparency and 

 delicacy of the shell. 



HY'ALINE. fr. gr. ualos, glass. Of 

 a glassy, thin and semi-transparent 

 substance. The pellucid sub- 

 stance which determines (lie spon- 

 taneous fission of cells. 



HY'BODONS. fr. gr. uios, bent out- 

 wards; orfows, tooth. A division 

 of the shark family, (p. 44, Book 

 viiij. 



HY'BRID. Mule; partaking of the 

 nature of two species. 



HY'DRA,-HYDRO. fr. gr. udor, water. 

 A prefix, denoting the presence of 

 water. 



HY'DRA. A minute fresh water 

 polyp. 



HY'DRATED. fr. gr. 'urfor, water. 

 Containing water. 



HY'DATIDS. fr. gr. 'udatis, a blad- 

 der. Name of certain entozoa. 



HYDA'TIS Lat. fr. gr. uddr, water. 

 Specific name of a mollusk. 



HYDRAU'LIC. fr. gr. ud6r, water; 

 aulos, a pipe. Relating to liquids 

 in motion. Hydraulics is that 

 branch of natural philosophy or 

 physics which treats of force of 

 water and other liquids in mo- 

 tion. 



HYDROCHLO'HIC ACID. An acid com 



