GRYPHAA. / 397 
opercular upper shell. The Gryphites are of a finer lami- 
nated structure than the oysters, and the ligament of the 
} 
Lien. 127. SHELLS AND ECHINITE FROM THE OOLITE AND LIAS. 
Fig. 1.—TRIGONIA CLAVELLATA. Ozford Clay, near Weymouth. 
2.—TRIGONIA GIBBOSA; a limestone cast. Jsle of Portland. 
3.—CIDARIS BLUMENBACHII. Oolite. Calne, Wilts. 
4.—TRIGONIA CosTATA. Oolite. Highworth, Wilts. 
5.—Spine of the Cidaris Blumenbachii. 
6.—GRYPHHA INcuRVA. Lias. Cheltenham. 
7.—AMMONITES WaLcoTil. Lias, near Bath. 
hinge is inserted in an elongated curved groove. There are 
about thirty British fossil species, none of which have been 
