GER- 



116 



GLA- 



of cells in a developing ovum, epi- 

 blast, hypoblast, and later mesoblast 

 (emb.). 



germinal spot, the nucleus of an 

 ooplasm (emb.). 



germinal vesicle, the nucleus of an 

 egg, before formation of polar- 

 bodies (emb.). 



germination (jer'inma'shun) n. [L. 

 germen, bud.] Beginning of growth ; 

 budding ; development (bot.). 



germiparity (jeYmipar'iti) n. [L. 



frmen, bud ; parere, to beget.] 

 eproduction by germ-formation. 



germogen ( j eVmoj Sn') n. [L. germen, 

 bud ; Gk. genos, offspring.] The 

 central cell of the gastrula-like 

 phase, or infusorigen, in the 

 development of the Rhombozoa ; 

 the residual nucleus, or unused 

 portion, after formation of the 

 rhpmbogen by division of the 

 primary germogen or primitive 

 central cell (zool.). 



gestation (jSsta'shun) n. [L. gerere^ 

 to carry.] The intra-uterine period 

 in the development of an embryo 

 (emb.). 



giant cells, large nerve-cells in 

 Annelids ; myeloplaxes ; osteo- 

 clasts ; large multinuclear proto- 

 plasmic masses found in marrow, 

 spleen (anat.). 



giant fibres, greatly enlarged and 

 modified nerve-fibres running longi- 

 tudinally through the ventral nerve 

 cord of some invertebrates, as 

 Worms (zool.). 



gibbous (gib'us) a. [L. gibbus, 

 humped.] Inflated ; saccate or 

 pouched, as the lateral sepals of 

 Cruciferae (bot.). 



gill (gll) n. [M.E. gille, gill.] A 

 plate-like or filamentous outgrowth ; 

 respiratory organ of water-inhabit- 

 ing animals (zool.) ; one of a number 

 of lamellae radiating from the stalk 

 of a mushroom (&?/.). 



gill arch, part of the visceral skele- 

 ton in the region of functional gills ; 

 branchial arch (zool.). 



gill basket, the branchial skeleton 

 of lampreys, composed of continu- 

 ous cartilage (zool.). 



gill book, the respiratory organ of 

 certain Arachnids, consisting of a 

 large number of leaf-like structures 



between which the water circulates 

 (zool.). 



gill cleft, a branchial cleft formed 

 on the side of the pharynx (zool.). 



gill cover, an operculum; 



gill helix, a spirally coiled gill-like 

 organ in certain Clupeidae (zool.). 



gill plume, the gill or ctenidium of 

 the majority of Gastropods (zool.). 



gill pouch, an oval pouch containing 

 gills and communicating directly or 

 indirectly by a duct with the 

 exterior, seen in Myxine and Petro- 

 myzon (zool.). 



gill rakers, small spine-like struc- 

 tures attached in a single or double 

 row to branchial arches to prevent 

 escape of food (sool.). 



gill remnants, epithelial, post- 

 branchial, or suprapericardial bodies 

 arising in the pharynx of higher 

 vertebrates (zool.). 



gill rods, oblique gelatinous rods 

 supporting the pharynx in Cephalo- 

 chorda (zool.). 



gill slits, a series of perforations 

 leading from pharynx to the exterior, 

 persistent in lower vertebrates, 

 embryonic in higher (zool.). 



gingival (jinjl'val) a. [L. gingivae, 

 gums.] Pert, the gums. 



ginglymoid (gmg'glTmoid) a. [Gk. 

 gingglymos, hinge - joint.] Con- 

 structed like a hinge-joint (anat.). 



ginglymus (ging'glimus) n. [Gk. 

 gingglymos, hinge-joint.] An ar- 

 ticulation constructed to allow 

 motion in one plane only (anat.). 



girdle (ger'dl) n. [A.S. gyrdan, to 

 gird.] In appendicular skeleton, 

 the supporting structure at shoulder 

 and hip, each consisting typically 

 of one dorsal and two ventral 

 elements (anat.). 



gizzard (giz'ard) n. [M.E. gizer, 

 gizzard.] In birds, the muscular 

 grinding chamber of the alimentary 

 canal ; the proventriculus of insects 

 (zool.). 



glabella (glabel'a) n. [L. glaber, 

 bald.] The space on the forehead 

 between the superciliary ridges 

 (anat.) ; the elevated median region 

 of the cephalic shield of Trilobites 

 (Pal.). 



glabrate (glab'rat) a. [L. glaber, 

 smooth.] Becoming smooth; glab- 



