ROTELLA. 249 



Melanioe, but placed by Sowerby near the Scalarise. They are 

 principally from the shores of the Mediterranean, and are also 

 very abundant on the British shores, as well as the East and West 

 Indian. Fig. 346, R. reticulata. 



ROBULUS. Montf. A genus of microscopic Foraminifera. 



ROLLUS. Montf. A genus composed of Conus Geographus, 

 Auct. fig. 462, and other species, rather cylindrical in form, and 

 having a coronated spire. 



ROSALINA. D'Orb. A genus of microscopic Foraminifera. 



ROSTELLARIA. (From rostrum, a beak.) Fam. Alatse, Lam, 

 Siphonostomata, Bl. — Descr. Turrited, fusiform, thick, smooth 

 or ribbed ; aperture oval, terminating anteriorly in a long canal, 

 posteriorly in a channel running up the spire ; outer lip dilated, 

 thickened, sometimes digitated, running up all or part of the 

 spire, with a sinus near the anterior canal ; inner lip smooth, 

 spread over part of the body whorl and of the spire. The Red Sea 

 and the Indian Ocean produce the few known species of this genus. 

 — Obs. Hippochrenes is the name given by De Montfort, to 

 those fossil species which have the outer lip simple and very much 

 dilated. R. curvirostrum, fig. 412. Aporrhais is a name given 

 to another proposed genus, composed of Rostellaria pes-pelecani, 

 Auct. fig. 404. and similar species. 



ROSTRATED. (From rostrum, a beak.) Having one or more 

 protruding points, as Tellina rostrata. 



ROTALIA. Lam. A genus of microscopic Foraminifera. The 

 same as Rotalites of De Montfort. 



ROTELLA. Lam. {A little wheel.) Fam. Turbinacea, Lam — 

 Descr. Orbicular, generally smooth, shining ; spire conical, de- 

 pressed, short ; aperture subtrigonal ; outer lip thin, angulated 

 near the centre ; inner lip spread over the surface of the whorls, 

 forming a thickened disc. Operculum horny, orbicular, spiral, with 

 numerous whorls. — Obs. The pretty little shells thus described 

 are found in seas of tropical climates. They are distinguished from 

 other genera of the family by their lenticular form and the orbicular 

 callosity of the under surface. Fig. 357, R. vestiaria. 



