ART. 20 ADDITIONAL MOLLUSKS FROM ECUADOK BAETSCH 15 



broadly oval ; posterior anirle obtuse : outer lip thin showing the ex- 

 ternal sculpture within; inner lip reflected over and appressed to 

 the base for about three-fourths of its length, leaving, however, a 

 narrow unbilical chink, and provided with a very strong oblique fold 

 at its insertion; parietal wall covered with a thick callus. 



The type (Cat. No. 363091, U.S.N.M.) has six and one-half post- 

 nuclear whorls and measures, length, 3 mm. ; diameter, 1 mm. 



ODOSTOMIA (CHRYSALLroA) PACKA, new species 

 Plate 2, iig. 0. 



Shell small, semitranslucent, bluish- white. Xuclear whorls decol- 

 lated. Postnuclear whorls slightly rounded, moderately shouldered 

 at the summit and marked by very strong decidedly retractively 

 slanting axial ribs, of which 14 occur upon the second and 16 upon 

 the rest. Intercostal spaces about one and one-half titaes as wide as 

 the ribs, well impressed, crossed by four rather strong, equal and 

 equally spaced spiral cords, of which the first is at the summit. 

 These cords pass strongly upon the sides of the ribs and render the 

 summit tuberculated, the tubercles being almost rounded, while the 

 spaces inclosed between the axial ribs and the spiral cords are oval 

 pits having their long axis parallel with the spiral sculpture. Suture 

 rendered channeled by the shouldered summit. In the third to last 

 suture, the peripheral cord becomes apparent, and this increases in 

 strength of exposure until on the last whorl it is fully exposed in 

 the suture. The axial ribs extend strongly across the space separat- 

 ing this cord from the first of the spire which is about as wide as 

 tliose on the spire, but the ribs do not render it tuberculated. Base 

 short, well rounded, marked by four strong spiral cords not includ- 

 ing the one at the peripliery. These grow progressively^ weaker from 

 the perpiheral cord to the one at the tip of the base, and also some- 

 what closer spaced. The broad channels separating the cords are 

 crossed by numerous slender axial threads. Aperture (?); outer 

 lip fractured; inner lip short, reflected over and appressed to the 

 base and provided with a strong fold at its insertion. 



The type (Cat. No. 363092, U.S.N.M.) has six and one-half whorls 

 and measures, length, 2.7 mm. ; diameter, 0.9 mm. 



ODOSTOMIA (CHRYSALLIDA) CAPA, r.cw species 



Plate 2, fig. 4. 



Shell very small, very elongate-ovate, milk-white. Nuclear whorls 

 well rounded, smooth, deeply obliquely immersed in the first of the 

 postnuclear whorls above which the tilted edge of the last volution 

 only projects. First postnucleai- Avhorl moderateh^ rounded, the next 



