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 : 

 *' 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; tinea, 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. 24 1 . 



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 Cypreea, 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. 



