RHOMBOIDAL. 247 



REPENT. {Repens, creeping.) A term applied to those shells, 

 which, being attached by the whole length of their shell, give the 

 idea of creeping or crawling. Ex. Verm ilia, fig. 7. 



RETICULATED. (Beticulatus.) Resembling net-work. 



RETIFERA. Bl. The first family of the order Cervicobranchiata, 

 Bl. containing the genus Patella. 



REVERSED or Sinistral Shells, are those in which the aperture 

 is on the left side of the shell, while it is held with the mouth 

 downwards, and towards the observer. Ex. Balea, fig. 296. 

 Attached bivalves are said to be reversed, when the left valve is 

 free, instead of the right; a circumstance which sometimes occurs 

 in Chama and Ostrea. 



RHEDA. Humph. Hyal^ea, Lam. 



RHINOCLAVIS. Sw. A genus of ' ' Cerithinaj," Sw. thus de- 

 scribed : " channel curved backwards, in an erect position; inner 

 lip very thick, with a tumid margin ; pillar generally with a 

 central plait ; operculum ear-shaped ; lineatum. En. M. 443, fig. 

 3, Vertagus. lb. f. 2, subulatum. Lam. No. 23, fasciatum. 

 Mart. 157, f. 1481. obeliscus, En. Meth. 443, f. 4 ; aluco, lb. 

 f. 5, (Aberrant,) semi-granosum. lb. 443, f. 1, asperum. Mart. 

 157, f. 1483. 



RHINOCURUS. Montf. A genus of microscopic Foraminifera. 



RHINODOMUS. Sw. A genus of " Scolyminse," Sw. thus 

 described : No internal grove ; shell clavate ; the spire longer 

 than, or equal with the aperture ; the whorls with ridges or 

 longitudinal varices, and rendered hispid by transverse grooves ; 

 inner lip wanting ; pillar with a terminal fold ; aperture striated ; 

 outer lip with a basal sinus. R. senticosus, Chem. tab. 193. f. 

 1864-1866. 



RHIZORUS. Montf. A genus described from a microscopic shell, 

 appearing to be a cylindrical Bulla. 



RHODOSTOMA. Sw. A sub-genus of " Turbininee," Sw. p. 344. 



RHOMBOIDAL. (pofxfiosicios, rhomboeidus.) Having a rhombic 

 form, i. e. four-sided ; two sides meeting at acute, two at obtuse, 



