102 G. Nevill — New or little-known [No. 3, 



regularly ribbed, ribs continuous (or almost so), very broad and massive, 

 slightly flexuous, the last whorl has 11 of these ribs, continued to its base ; 

 aperture ovate, slightly oblique, without any basal canaliculation, with the 

 margins much thickened and continuous, joined by a well marked callosity. 



Long. 2f , diam. 1 mil. 



Abundant at Ceylon, also Mauritius, Andamans, Bourbon, Aden, and 

 Roweiah. 



Type, Indian Museum (from Ceylon) ; also in coll. Weinkauff, Dohrn, 

 Hungerford, and Baxter. 



This pretty little species is the type of my section, or subgenus, 

 Schivartziella ; R. orientalis has hitherto been confused by Herr Schwartz 

 von Mohrenstern and other conchologists with its close ally, the R. scalari- 

 formis, C. B. Adams, from Panama. It can, however, be sufficiently 

 distinguished by its less elongate form, of one whorl less, and especially 

 by the mammillate instead of " acute" apex, the aperture is less oblique, the 

 ribs bluntly broad, instead of " acute," &c. 



After a long examination under a lens, I am unable to detect any signs 

 of transverse striation in my Ceylon specimens, though they are in fresh 

 and perfect condition. 



RlSSOIFA BLANFOEDIATSA, n. sp. PI. VI, Fig. 16. 



Lanceolately produced, in shape resembling R. desliayesi, Schwartz, 

 but the more convex whorls give it a less turreted appearance ; white, rather 

 solid, spire conically elongate, very acute, apex not mammillate, suture 

 rather indistinct, especially on the upper whorls ; whorls 10 to 11, convex- 

 ly turreted, longitudinally ribbed with rather distant, acutely raised, almost 

 straight ribs, which are evenly decussated with a transverse, rather distant 

 striation, the striae of approximately the same developement as the ribs, 

 but slightly subnodulose at the points of intersection, the last whorl is 

 short and convex much as in R. deshayesi, but with only 13 — 14 ribs instead 

 of " 22 — 24," there are 6 of the regular, well developed transverse striae 

 and two others much finer and more crowded together next the suture, the 

 basal transverse rib is evenly granulose, moderately developed ; aperture 

 rather large, with the peristome boldly rounded, somewhat dilated towards 

 the base, the columellar emargination is broad, but shallow and very un- 

 like the markedly incised one of its ally, compared by Herr Schwartz to 

 that of a Cerithium ; the outer lip is only moderately thickened. 



Long. 9f , diam. 3f mil. 



Annesley Bay, Red Sea ; rare. 



Type, Indian Museum. 



