NO. 1452. NOTES ON PYRAMIDELLIDJ<:~DALL AND BARTSCH. 863 



whorls rather high between the sutures, very slij^htly rounded, slightly 

 angulated at the periphery and scarcely at all shouldered, marked b}'^ 

 scarcel}^ perceptible lines of growth, and here and there b}^ a faint 

 trace of some ver^- tine microscopic spiral lines. The summit of suc- 

 ceeding whorls falls somewhat anterior to the periphery of the pre- 

 ceding turns, which gives a slightly constricted appearance at the well- 

 impressed suture. Periphery of the last whorl faintly angulated; 

 base large, well rounded, narrowly umbilicated and somewhat effuse 

 at the junction of the lip and columella, posterior angle acute, outer 

 lip (fractured), thin, columella long, .slender, almost straight, some- 

 what revolute, bearing a strong oblique fold near its insertion; parietal 

 wall covered by a thin callus. 



The specimen described is Dunker's type which comes from Desima, 

 Japan. It is not quite mature, having seven and one-half post-nuclear 

 whorls and measures: long. 5.8 mm. ; diam. 2.2 mm. The Dunker col- 

 lection contains an additional specimen from Nagasaki, Japan, of 

 which we also give a figure. This is adult. It has nine post-nuclear 

 whorls and measures: long. 6.Y mm.; diam. 2.8 mm. The chief differ- 

 ence between this and the 3"oung .shell lies in the aperture, the outer 

 lip in this case being rather patulous. The Pa?tel collection has one 

 specimen from Nagasaki, Japan. 



ODOSTOMIA (ODOSTOMIA) MAURITIANA, new species. 

 Plate XXVI, fig. 6. 



Shell small, umbilicated, elongate-ovate conic, semitransparent, pol- 

 ished. Nuclear whorls two and one-half, moderately" large, helicoid, 

 elevated, about one-fffth immersed in the first of the succeeding whorls 

 and having their axis at a right angle to them. Post-nuclear whorls 

 flattened, angulated at the periphery and weakly shouldered at the 

 summit; the latter falls somewhat anterior to the peripherj^ of the pre- 

 ceding whorl and lends to it a somewhat constricted appearance at 

 the well-impressed suture. The whorls are marked by extremely fine, 

 closely placed, wav}- spiral striations, which are visible only under 

 very high magnification. Peripher\^ of the last whorl somewhat angu- 

 lated. Base very broad, gently rounded, somewhat pinched at the nar- 

 row umbilicus. Aperture elongate-ovate, somewhat prolonged at the 

 junction of the outer lip and cokimella; posterior angle acute, outer lip 

 thin, somewhat effuse, columella slender, decidedly curved, slightly 

 revolute, provided with a prominent oblique fold at its insertion; 

 parietal wall covered by a strong callus which lends the peritreme an 

 almost continuous appearance. 



The specimen described and figured belongs to the Ptetel collection 

 and comes from Mauritius. It has five post-nuclear whorls and meas- 

 ures: long. 2.1 mm.; diam. 1.1 mm. 



