246 REOPHAX. 



RANGIA. Desmoulins. Gnathodon, Gray. 



RAPANUS. Schum. ? A genus consisting of species of Pyrula, 

 Auct. which are thin, much inflated, with short canals. Fig. 

 389, P. papyracea. 



RAPELLA. Sw. A genus of " Pyrulinse," Sw. thus described : 

 1 ' Shell ventricose, generally thin, almost globose; the base 

 suddenly contracted, and forming a short canal, the channel 

 almost obsolete ; umbilicus large, partly concealed by the inner 

 lip. R. papyracea. En. Meth. 436, f. 1." Sw. p. 307- Rapanus, 

 Schum. Fig. 389. 



RAPHANISTER. Montf. A species of madrepore, described as 

 a shell. 



RAPUM. Humph. Turbinella, Lam. 



RAZOR SHELL. A common name by which shells of the genus 

 Solen, are known in the market. 



RECTILINEAR. (Rectus, right; linea, a line.) In a straight 

 line. Ex. The hinge of Byssoarca Nose, fig. 132. 



RECURVED. (Re, back ; curvo, to bend.) Turned backwards ; 

 the term, when applied to symmetrical conical univalves, is used 

 to signify that the apex is turned towards the posterior margin, 

 as in Emarginula, fig. 241. 



REFLECTED. (Reflected, to fold back.) Turned, or folded back- 

 wards. Ex. The edge of the outer lip in Bulinus, fig. 282, is 

 reflected, while that of Cyprsea, fig. 445 to 450, is inflected. 



REMOTE. (Remotus, distant.) Remote lateral teeth in a bivalve 

 shell, are those that are placed at a distance from the cardinal 

 teeth. Ex. The lateral teeth of Aphrodita, (fig. 123.) are remote; 

 those of Donax, (fig. 108) are near. 



RENIELLA. Sw. A sub-genus of Malleus. Lardn. Cyclop. Malac. 

 p. 886. Gray states it to be only a distorted specimen of Vulsella, 

 Syn. B. M. p. 145. 



RENIFORM. (Ren, a kidney; forma, shape.) Shaped like a 

 kidney. Ex. The aperture of Ampullaria, fig. 318. 



RENULINA. Lam. A genus of microscopic Foraminifera. 



REOPHAX. Montf. A genus of microscopic Orthocerata, Bl. 



