278 GLOSSARY OF EMBRYOLOGICAL TERMS 



Field, Morphogenetic — embryonic field out of which will normally develop 

 certain specific structures. 



Flexure — refers to a bending such as cranial, cervical, and pontine flexures. 

 Also dorsal and lumbo-sacral flexures of the pig. 



Follicle — cellular sac within which egg generally goes through early matu- 

 ration stages. 



Forebrain — most anterior of first three primary brain vesicles, associated 

 with lateral opticoels. (Syn., prosencephalon.) 



Foregut — more anterior portion of enteric canal, first to appear, aided by 

 development of pharyngeal derivatives. 



Fovea Germinativa — pigment-free spot of animal hemisphere where am- 

 phibian germinal vesicle gives off its polar bodies. 



Frontal — plane at right angles to both transverse and sagittal, dividing dor- 

 sal from ventral. (Syn., coronal.) 



Gamete — differentiated (matured) germ cell, capable of functioning in 

 fertilization (e.g., sperm or egg cell, germ cell). 



Gametogenesis — process of developing and maturing germ cells. 



Ganglion — aggregation of neurons, generally derived from a neural crest 

 (e.g., cranial and spinal ganglia). 



Ganglion, Acoustic — eighth cranial ganglion from which fibers of eighth 

 cranial nerve arise, purely sensory. 



Ganglion, Acustico-facialis — early undifferentiated association of seventh 

 and eighth cranial ganglia. 



Ganglion, Gasserian — fifth cranial ganglion, carrying both sensory and 

 motor fibers. (Syn., trigeminal ganglion, semilunar ganglion.) 



Ganglion, Geniculate — ganglion at root of facial (VII) cranial nerve, 

 carrying both sensory and motor fibers. 



Ganglion, Nodosal — ganglion associated with vagus (X) cranial nerve 

 which carries afferent fibers to pharynx, larynx, trachea, oesophagus, 

 and thoracic and abdominal viscera. 



Ganglion, Petrosal — ganglion associated with glossopharyngeal (IX) cra- 

 nial nerve, more peripheral than superior ganglion carrying sensory 

 fibers from pharynx and root of tongue. 



Ganglion, Superior — ganglion associated with glossopharyngeal (X) cra- 

 nial nerve, mesial to petrosal ganglion. 



