46 GLYCIMERIS., 
GAS'TERO'PODA. Lam. (Laszmp, gaster, belly ; toda, poda, feet. ) 
The second order of the class Mollusca, Lam. containing 
those molluscous animals whose organs of locomotion are 
ventral. This order is divided into Hydrobranchiata and 
Pneumobranchiata. Fig. 227, to 263. 
GASTRA’NEA. Schum? Corsuua, Auct. 
GASTROCHAVNA. Speng. (Tasznp, gaster, belly ; xaww, chaino, 
gape.) Fam. Pholadaria, Lam. Pyloridea, Bl. Deser. 
Equivalve, regular, inequilateral, with a wide, oblique, ventral 
hiatus, enclosed in a curved, pyriform tube. Differing from 
Galeomma in being a free, oblique shell; from Fistulana, in the 
oval shape of the valves, and the curve of the tube; from 
Aspergillum and Clavagella, in both valves being free. Obs. 
The Gastrocheenze are found in the hollows of shells or other 
marine substances. Fig. 52, G. Mediolina. 
GAS TROPLAX. Bl. Umsreuia, Lam. 
GEOPONUS. Montf. A genus of microscopic Foraminifera. 
GEOTROCHUS. Sw. Hexix Pileus, Auct. Fig. 278, and other 
trochiform species. 
GERVIL'LIA. Defr. Fam. Margaritacea, Bl. Malleacea, Lam. 
Descr. Equivalve, oblong, oblique; hinge long, straight, having 
small, irregular transverse ligamentary pits. Obs. This genus of 
fossil shells, found at various geological periods, from the Lias to 
the Baculite limestone in Normandy, is now extinct. In 
general form, it resembles Avicula, but in the hinge it approaches 
Perna. Fig. 169, Gervillia Avicularis. 
GIB’BUS. Montf. Buiinus Lyonetianus, Lam. Pupa, Bl. fig. 284. 
GIOE'NIA. Name given in the Encyclopédie Methodique, to 
the plates of the stomach of Bulla Lignaria. 
GLANDINA. Schum. PotypHemus, Montf. 
GLANDIO’LUS. Montf. A genus of microscopic Foraminifera. 
GLAUCON'OME. Gray. Fam. Solenacea, Lam. Deser. Ob- 
long or oval, transverse, slightly ventricose, equivalve, inequi- 
lateral; margins close, rounded anteriorly, somewhat acuminated 
posteriorly ; hinge teeth three in each valve, of which the central 
in one valve, and the posterior in the other, are bifid; muscular 
. impressions, anterior, elongated, marginal; posterior, sub-qua- 
drate; palleal impression having a long sinus; ligament oblong, 
external; epidermis thin, horny, green, folded over the margins. 
Obs. This shell, of which only one species is known, inhabits 
some of the rivers of China. C. Chinensis, fig. 64. 
GLOBIGERI'NA. D’Orb. A genus of microscopic Foraminifera. 
GLYCIM’ERIS. Lam. Fam. Solenacea, Lam. Pyloridea, Bl. 
Descr. Equivalve, transverse, oblong, thick, compressed, gaping 
at both extremities; hinge callous, without teeth; ligament 
large, external, prominent; epidermis thick, black, horny, folded 
over the margins; muscular impressions two, distant, running 
