ICTHTOSAECOLITES. 173 



HTGEOMANES. Per. A sub-division of Helix, containing 

 H. limbata, Auct. &c. Gray's Turton, p. 143. 



HTPOTHTEIS. Phillips, King, 1846. A genus represented 

 by Terebratula psittacea. PI. xi. fig. 202. 



HTEIA. Lamarck, 1819. A genus composed of species of 

 Nayades, distinguished by their alated dorsal margins, and lamel- 

 Lated lateral teeth. South America. IIteia corrugata, fig. 143, 

 Hyria Syrmatophora. PI, viii. fig. 144. 



HTEIDELDA. Swainson, 1840. A genus of " Hyrianfe," Sw. 

 described as differing from Hteia, Auct. in haviag a cardinal 

 as well as a lateral tooth in each valve. Sw. p. 380. 



HISTEIX. Humphrey, 1797. Eicikula, Auct. 



JAIS'IEA. Schum. 1817. A genus composed of species of Pecten, 

 Auct. having oblique plicae or calli on each side of the ligamen- 

 tary pit. Ex. P. plica, fig. 172. Decadopecten, Eiippell. 



JANTHINA. Bolton, 1798. (Janfkum, a violet.) Fam. JN'erita- 

 cea. Lam. Osystomata, Bl. — Descr. Sub-globose, thin, fragile ; 

 spire short, consisting of few whorls ; aperture angulated, at the 

 anterior junction of the inner and outer lips; columella tor- 

 tuous, contiguous to the axis ; outer lip thin, sinuated in the 

 centre.— 055. The shells composing this genus are celebrated 

 for their beautiful purple colour. The animal possesses a small 

 vesicular process, which keeps it fioatiag on the surface of the 

 water ; it exudes a purple secretion when irritated. It is occa- 

 sionally floated on to the shores of most temperate and tropical 

 countries. J. Pragilis. PL xv. fig. 333. 



JATAE0:N"TJS. Adanson. Chama, Auct. 



IBDEUS. Montf. Caeocolla, Lam. 



IBLA. Leach, 1825. Fam. Pedunculated Cirripedes, Lam. — 



• Descr. Eour valves, posterior pair elongated, anterior pair short, 

 triangular ; pedicle cylindrical, contracted at the base, hairy. — 

 Obs. I. Cuveriana, is brought from Kangaroo Island. PL ii. 

 fig. 40. 



ICTHTOSAECOLITES. Desmarest. Fam. Ammonacea, Lam, 

 — Descr. Chambered, slightly arcuate, laterally compressed; 



