ART. 14. NEW MOLLUSKS FROM ECUADOR BAETSCH. 5 



separating the twenty-second from the twenty-third is much wider 

 than the rest and appears like a smooth girdle. Periphery of the 

 last whorl well rounded. Base short, well rounded, marked by 

 twenty-five fine, incised spiral lines, those on the columella separating 

 cords a little stronger than the rest. 



The type. Cat. No. 359758, XJ.S.N.M., has 8.5 postnuclear whorls 

 and measures ; length, 4.5 mm. ; diameter, 1.3 mm. 



TURBONILLA (STEIOTURBONILLA) THYNE, new species. 



Plate 1, fig. 2. 



Shell very regularly conic, subdiaphanous, bluish white. Nuclear 

 whorls two and a half, forming a moderately elevated spire, the axis 

 of which is at right angles to that of the succeeding turns, in the 

 first of which the nuclear spire is about one-third immersed. Post- 

 nuclear whorls slightly rounded, narrowly shouldered at the summit, 

 marked by strong, retractively slanting, slightly curved axial ribs, 

 of which 14 occur upon the first and second, 16 upon the third to 

 sixth, and 18 upon the last turn. These ribs extend prominently 

 from the summit, which they render slightly wavy, to the periphery. 

 Intercostal spaces a little wider than the ribs, strongly impressed, 

 terminating at the periphery. Suture moderately constricted. Pe- 

 riphery of the last whorl well rounded. Base short, well rounded, 

 smooth. Aperture subquadrate; posterior angle acute; outer lip 

 thin, showing the external sculpture within; inner lip almost ver- 

 tical, slightly flexuous, reflected over the posterior half to the base, 

 provided with an obsolete fold a little anterior to its insertion. 



The type. Cat. No. 359759, U.S.N.M., has almost 8 whorls and 

 measures : length, 3.4 mm. ; diameter, 1.1 mm. 



The extremely regular conic outline and large ribs will distinguish 

 this from any of the other species. 



TURBONILLA (PYRGISCUS) MELEA, new species. 



Plate 2, fig. 8. 



Shell very slender, elongate-conic, yellowish white, with a little 

 deeper yellow band about one-fourth of the distance between the 

 summit and the suture anterior to the summit. Nuclear whorls and 

 early postnuclear whorls decollated. Postnuclear whorls very high 

 between summit and suture, appressed at the suimnit, marked by 

 broad, low, rounded, almost vertical axial ribs, of which 20 occur 

 upon the first and second of the remaining turns, 21 upon the third 

 and fourth, and 28 upon the last whorl. Intercostal spaces about 

 half as wide as the ribs, marked by 18 slender spiral threads \Vhich 

 leave the spaces between them as deeply impressed oblong pits. 



