174 lifEQUIYALVE. 



septa simple, leaving triangular articulations imbricated like the 

 thick muscles of a fish. 

 JEPEEEYSIA. Alder. A genus of small shells separated from 

 Eissoa on the ground of a peculiarity in the operculum. Ex. 

 J. Diaphana, Eorbes aud Hanley. British Mollusca, No. 30. 

 PI. cli. fig. 76. 

 JESITiES. Montf. A minute fossil resembling GtAleolaeia. 

 ILOTES. Montf. Oebtctjltna, B1. A genus of microscopic 



Eoraminifera. 

 IMBEICAEIA. Schumacher, 1817. Conohelix, Sw. 1833. 



See MiTEA. 

 IMBEICATED. (Imbrex, a tile.) A shell is said to be imbri- 

 cated when the superficial laminae are arranged over each other 

 in the manner of tiles. 

 IMPEEATOE. Montfort, 1810. A genus composed of species 

 of the genus Teochtjs, Auct. with whorls angulated and stel- 

 lated, having an umbilicus. Ex. T. Imperialis. 

 IMPEESSIOJS". See Musculae Impeessiott. 

 INCEASSATED. (Crassus, thick.) Thickened, as the hinge of 



Glycimeris, fig. 67. 

 INCTJEVED, Turned inwards or bent forwards. Applied to 

 symmetrical shells, when the point of the apex turns towards 

 the anterior extremity, as in Patella. The apex of a shell is said 

 to be curved when it is bent inwards, but not sufiiciently so to 

 be described as spiral. Ex. Ammonocesas, Lam. fig. 477. 

 INDENTED. (In, in ; dens, a tooth.) Exactly the reverse of 

 Dentated ; meaning a series of small cavities, such as might 

 be produced by the entrance of teeth. The cast of a dentated 

 surface would be indented. 

 INEQTJILATEEAL. (Mquus, equal; latus, a side.) A term ap- 

 plied to a bivalve shell when its extent on one side of the um- 

 bones is greater than that on the other. When the sides are 

 nearly equal, the term sub-equilateral is used. 

 INEQUIYALVE. (in ; eequus, equal ; valva, valve.) The two 

 principal valves differing from each other in diameter or con- 

 vexity. 



