216 PATELLA. 



PARACEPHALOPHORA. Bl. The second class of the type Ma- 

 lacozoa, Bl. divided into the sub-classes : P. dioica, P. monoica, 

 P. hermaphrodita. 



PARIES. (A wall.) The principal part of a multivalve shell, 

 forming a circular wall round the body of the animal, and com- 

 posed of one or more valves which are called the parietal 

 valves. 



PARIETAL VALVES. The principal valves of multivalve shells 

 surrounding the body like a wall ; as distinguished from the 

 opercular valves, or those which compose the operculum. 



PARMACELLA. Cuv. (A little cell.) Fam. Limacinea, Lam. 

 and Bl. — Descr. Haliotoid, internal, thin ; spire flat, consisting 

 of one or two rapidly increasing whorls ; aperture as large as the 

 whole shell, with the dorsal margins inflected. — Obs. This de- 

 scription applies to Parmacella of Cuvier. The shell figured in 

 Sowerby's Genera under that name is Cryptella of Webb. Fig. 

 257, P. Olivieri. Fig. 258, P. Pallidum. 



PARMOPHORUS. Bl. A genus composed of Emarginula elon- 

 gata, Auct. and other species of a similarly elongated form. Aus- 

 tralian. Fig. 242. P. elongatus. 



PARTULA. Fer. Fam. Colimacea, Lam. Auriculacea, Fer. — 

 Descr. Conical, smooth ; spire equal to the aperture in length, 

 consisting of few whorls ; aperture auriform ; outer lip reflected, 

 broad ; inner lip reflected, with a slight prominence on the colu- 

 mella. P. austrahs, fig. 302. 



PASITHiEA. Lea. A genus formed of some pyramidal shells, 

 described as resembling Melania, but separated from that genus 

 on account of being marine fossils. Fig. 317, P. striata. 



PATELLA. Auct. (A dish or platter.) Fam. Phyllidiana, Lam. 

 Retifera, Bl. — Descr. Symmetrical, compresso-conical, nearly 

 regular, oblong or oval ; apex sub-central, inclining towards, the 

 anterior margin ; aperture oval, forming the base of the shell ; 

 internal surface smooth ; with a muscular impression shaped like 

 a horse-shoe, with the ends bending forwards, encircling and 

 dividing the space all round, except where the interruption occurs 



