GLOSSARY. 137 



named, fr->m its wreathing its thread-like body into knots, after tho mythical 

 king of Phrygia the knot of whose waggon was cut by Alexander. 



GYMNOL^EMATA (yv/j.vos, naked ; A.ot/xo's, throat), an order of Polyzoa in which the 

 opening to the gullet is uncovered. 



GYMNOPHIOXA (yv/j.v6s, naked ; 6cf>is, snake^ , an order of Amphibia, otherwise 

 called Ophiomorpha or Cxcilix. 



GYMNOPHTHALMATA (yjfj.v6s, naked ; o(j>9a\/j.6s, eye), the craspedote Medusae of the 

 class Hydrozoa. 



HALLUX (hallex or allex, the great toe), the innermost of the five normal digits of 

 a vertebrate foot. 



HALTEKES (a.\rrjpes, fr. aAAo/uu, to leap), poisers, weights held in the hand in 

 leaping, applied to the modified second pair of wings of Diptera. 



HELJIIXTHLE (e\u.ws, a worm, fr. el\ia, to twist), a synonym of Entozoa, divided 

 by Owen into Sterelmintha (ff-repe&s, solid), the Parenchymata of Cuvier, and 

 Coelelminthia (/cotAos, hollow), the Cavitaria of Cuvier. They are all included 

 in the class Scoledda. 



HEMIPTEBA wu-, half; irrspfo, a wing), an order of Insects with the anterior 

 wings half coriaceous. 



HETEKOPODA (frepos, different from others ; irovs, foot), a group of branchial 

 Gasteropoda in which the propodium is turned into a laterally compressed 

 fin, while the epipodia are absent. 



HOLOTHUUIA (d\oQovpiov Arist. H. A. i., i. 19), a genus to which the Sea- 

 cucumbers and Trepangs belong, which gives its name to the order Holo- 

 thuridea. 



HOMOLOGY (6/j.o\oyia, agreement), the relation between parts which are developed 

 out of the same embryonic structures ; as the arm of a man, the foreleg of a 

 horse, and the wing of a bird, or th j wings " of a pteropod, and the tentacles 

 of a cuttle-fish. The term Serial Homology is applied to the likeness between 

 parts which appear to be the modified development of structures similarly 

 repeated, as the humerus and femur in Vertebrata, or the maxillae, maxillipeds, 

 and ambulatory limbs of Crustacea, 



HUMERUS (brachium, ppaxitav), the bone of the upper arm in Vertebrata. 



HYDATID (uSfm's), or Bladder-worm, the cystic form of the wandered scolices of 

 tape-worms. 



HYDRA (u'Spo, a water-dragon), a genus of Polyps first described by Trembley in 

 1774, which forms the type of the modern class Hydrozoa. 



HYMENOPTEKA (y^fy, a membrane ; irrep6v, wing), an order of Insects with two 

 pair of wings, both membranous. 



HYOID (T, elSos, resemblance), also called os linguae from its supporting the tongue, 

 a bone named from its resemblance to the letter U in Man : in most other 

 animals it is much more complicated, the lesser cornua forming with the stylo- 

 hyoid ligaments long jointed bones which connect it with the skull. 



HYRAX (fy>a|, sarex, a shrew), the Daman, the Coney (i. e., Rabbit) of Scripture, 

 a small gregarious mammal found in Syria and South Africa. Linnaeus put 

 it among Bodentia, Cuvier under Pachydermata ; but its peculiarities are so 

 great that it may form the type of a distinct order, Hyracoidea. 



ICHTHYOPSIDA (ix"" s > a ^ sn ' fyis, appearance), a primary division of Vertebrata, 

 which includes the classes Pisces and Amphibia. 



ICHTHYOSAURUS (ixQvs, a fish ; a-avpa, a lizard), an extinct genus of Reptiles, giving 

 its name to the order Ichthyosauria. 



IMAGO, applied by Limueus to the final, winged and sexual state of Insects. 



