298 MANUAL OF ZOOLOGY. 



GASTEROPODA (Gr. paster, stomach ; pous, foot). The class of the Mollusca, 

 comprising the ordinary univalves, in which locomotion is usually effected 

 by a muscular expansion of the under surface of the body (the 'foot'). 



GEMMAE (Lat. gemma, a bud). The buds produced by any animal, whether 

 detached or not. 



GEMMATION. The process of producing new structures by budding. 



GEMMIPAUOUS (Lat. gemma, a bud ; pario, I produce). Giving origin to new 

 structures by a process of budding. 



GEMMULES (Lat dim. of gemma). The ciliated embryos of many Coelen- 

 terata ; also the seed-like reproductive bodies, or ' spores,' of Spongilla. 



GLADIUS (Lat. a sword). Applied to the horny endoskeleton, or ' pen,' of 

 certain Cuttle-fishes. 



GNATHITES (Gr. gnathos, a jaw). The masticatory organs of Crustacea. 



GONOBLASTIDIA (Gr. gonos, offspring; blast idion, dim. of llastos, a bud). 

 The processes which carry the reproductive receptacles, or ' gonophores,' 

 in many of the Hydrozoa. 



GONOCALYX (Gr. gonos ; and kalux, cup). The swimming-bell in a medusi- 

 form gonophore, or the same structure in a gonophore which is not 

 detached. 



GONOPHORE (Gr. gonos ; and phero, I carry). The generative buds, o-r re- 

 ceptacles of the reproductive elements, in the Hydrozoa, whether these 

 become detached or not. 



GONOSOME (Gr. gonos ; and soma, body). Applied as a collective term to 

 the reproductive zooids of a Hydrczobn. 



GONOTHECA (Gr. gonos ; and theke, a case). The chitinous receptacle, within 

 which the gonophores of certain of the Hydrozoa are produced. 



GRAPTOLITID-E (Gr. grapho, I write ; lithos, stone). An extinct sub-class of 

 the Hydrozoa. 



GUARD. The cylindrical fibrous sheath with which the internal cham- 

 bered shell (phragmacone) of a Belemnite is protected. 



GYMNOUEMATA (Gr. gumnos, naked ; laima, the throat). An order of the 

 Polyzoa, in which the mouth is devoid of the valvular structure known 

 as the ' epistome.' 



GYMNOPHTHALMATA (Gr. gumnos ; and ophthalmos, the eye). Applied by Ed- 

 ward Forbes to those Medusae in which the eye-specks at the margin of 

 the disc are unprotected. The division is now abandoned. 



GYMNOSOMATA (Gr. gumnos, and soma, the body). The order of Pteropoda, 

 in which the body is not protected by a shell. 



GYNOPHORES (Gr. gune, woman ; phero, I carry. The generative buds, or 

 gonophores, of Hydrozoa, which contain ova alone, and differ in form from 

 those which contain spermatozoa. 



HAEMAL (Gr. haima, blood). Connected with the bloodvessels, or with the 

 circulatory system. 



HALTERES (Gr. halteres, weights used by athletes to steady themselves in 

 leaping). The rudimentary filaments, or ' balancers,' which represent the 

 posterior pair of wings in the Diptera, an order of Insects. 



HATTSTELLATE (Lat. haurio, I drink). Adapted for sucking or pumping up 

 fluids ; applied to the mouth of certain Crustacea and Insecta. 



HECTOCOTYLUS (Gr. heJcaton, a hundred; Jcotulos, a cup). The metamor- 

 phosed reproductive arm of certain of the male Cuttle-fishes. In the 

 Argonaut the arm becomes detached, and was originally described as a 

 parasitic worm. 



HELMINTHOID (Gr. helmins, an intestinal worm). Worm-shaped, vermiform. 



HEMELYTHA (Gr. hemi, half; elutron, a sheath). The wings of certain insects, 



