RANELLA. 



245 



RADIOLATA. Lam. A family belonging to the order Cepha- 

 lopoda, Lam. The shells belonging to it are described as dis- 

 coidal, with the spire central, and the chambers radiating from 

 the centre to the circumference. This family contains the genera 

 Rotalina, Lenticulina, and Placentula. 



RADIOLITES. A genus belonging to the family of Rudistes, 

 differing from Sphserulites, in having both the valves more conical. 



RADIUS. Montf. A genus composed of Ovulum Volva, Auct. 

 and other similar species, having a long attenuated canal at each 

 extremity. Fig. 442. 



RADIX. Montf. A genus composed of species of Limn^ea, 

 having a short spire and wide aperture. — Ex. L. aperta, fig. 309. 



RAMIFIED. (Ramus, a branch.) Branched out.— Ex. The varices 

 of some Murices, &c. 



RAMPHIDOMA Schum. Pollicipes, Leach 



RAMOSE. (Ramosus, branched.) Spread out into branches. 

 Ex. Murex inflatus, fig. 395. 



RANELLA. Auct. (Rana, a frog.) Fam. Canalifera, Lam. 

 Siphonostomata, Bl. — Descr. Oval or oblong, depressed, thick, 

 with two rows of continuous varices, skirting the outline, one 

 on each side ; spire rather short, pyramidal, acute, aperture 

 oval, terminating in a canal at each extremity ; outer lip thickened 

 within, crenulated, or denticulated, forming an external varix ; 

 inner lip spread over a portion of the body whorl. — Obs. The 

 shells composing this well-defined genus, are for t lie most part 

 covered with tuberculations, and granulations, and from the colour 

 and squat shape of some species, have been likened to frogs. The 

 Ranellse are mostly inhabitants of the East Indian seas. The few 

 fossil species known, occur in the tertiary beds. The two conti- 

 nuous rows of varices skirting the spire, distinguish this genus from 

 Triton, which it nearly approaches, and into which some species 

 run by imperceptible gradations. Fig. 393, 394. Many new 

 species were brought to this country by Mr. Cuming, and are 

 represented in parts 84, 85, 88, 89, 92, 93, of the author's 

 Conchological Illustrations. 



