GLOSSAKT. 277 



Germ-cell or Germ-vesicle. "The first nucleated cell that appears 



in the impregnated ovum " ( Owen). 

 Germ-lamellcB. The two primary layers of the embryo epiblast 



and hypoblast in the Metazoa ; in the great majority a third 



layer (mesoblast] is developed. 

 Gigerium gizzard. The muscular stomach of certain birds and 



insects. 



Glabellum. The central ridge in the shield of the Trilobites. 

 Gland. An organ that secretes certain constituents of the blood, 



which are then voided by a duct. 

 Glossarium. The middle portion of the suctorial proboscis in 



the Diptera. 



Glottis. The opening of the larynx. 

 Gnathites. The masticatory organs of the Crustacea. 

 Gnathopod. See Maxillipedes. 

 Gonangium. A " receptacle " in which, in some of the Hydrozoa, 



planoblasts or sporosacs are developed. 

 Gonoblastidiuwi. See Blastostyle. 

 Gonocalyx. The swimming-organ of the gonophore of a Hydro- 



zoon. 

 Gonocheme. A sexual medusa. " A medusiform planoblast, which 



gives origin directly to the generative elements " (Allmari). 

 Gonophore. " The ultimate generative zooid (in the Hydrozoa), 



which gives origin directly to the generative elements, ova or 



spermatozoa" (Allmari). 



Gonosome. The assemblage of sexual zooids in the Hydrozoa. 

 Gonotheca. A peculiar ovigerous capsule in some of the Hy- 

 drozoa. 



Gyncecomasty. Milk-secretion in the breast of man. 

 Gynophores. The generative buds of the Hydrozoa which con- 

 tain the ova only, not the spermatozoa. 



Habit. See Fades. 



Haemal. Connected with the blood-system. 



Hcemapophyses. Processes of the vertebrae ; in the Eeptilia they 



form the abdominal ribs. 



Hallux. The great toe, or the innermost digit. 

 Halteres. Small clavate filamentous organs, one on each side the 



metathorax of the Diptera ; supposed to represent the posterior 



wings. 



