42 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



TURBONILLA cSTRIOTURBONILLA) STEPHANOGYRA, new species. 

 Plate 3, figs. 8, 8«. 



Shell elongate-conic, milk-white. Nuclear whorls three, forming 

 a well-elevated spire, the axis of which is at right angles to that of 

 the succeeding turns, in the first of which they are about one-fifth 

 immersed. Post-nuclear whorls decidedly flattened, w^ith strongly 

 beveled shoulders, marked by strong, almost cylindrical, narrow, 

 well rounded, vertical axial ribs, of which 14 occur upon the first to 

 third, 16 upon the fourth to sixth, and IS upon the remaining turns. 

 Intercostal spaces about twice as wide as the ribs, well impressed, 

 with a decidedly pinched-in area near the summit, which gives this 

 part of the shell a step-like aspect. Sutures well marked. Periphery 

 and base of the last whorl well rounded. Entire surface of spire and 

 base marked by exceedingly, fine, closely spaced, spiral striations. 

 Aperture rhomboidal, rather long ; outer lip thin, showing the external 

 sculpture within; columella slender, almost straight. 



The type (Cat. no. 162440 U.S.N.M.) was dredged at U. S. Bureau 

 of Fisheries station 2799, in 29| fathoms, in the bay of Panama. It 

 has ten ])ost-nuclear whorls, and measures: Length 4.8 mm., diameter 

 1.3 mm. 



TURBONILLA (STRIOTURBONILLA) PANAMENSIS C. B. Adams. 



Plate 3, figs. 12, 12a. 



Chemnitzia panamensis C. B. Adams, Ann. Lye. Nat. Hist, of N. Y., vol. 5, 1852, 

 p. 392. 



Shell with the sides of the spire forming a straight line, light yellow. 

 Nuclear whorls small, two and two-thirds, forming a quite elevated 

 spire, the axis of which is at right angles to that of the succeeding 

 turns, in the first of which they are about one-fourth immersed. 

 Post-nuclear whorls rather low between the sutures, decidedly flat- 

 tened and slightly shouldered at the summit, marked by strong, 

 rounded, very protractive axial ribs, which are of equal strength 

 from the summit to the periphery, of these 16 occur upon the first 

 seven whorls, 18 upon the eighth, 20 upon the ninth, 22 upon the 

 tenth, and 25 upon the penultimate turn. Intercostal spaces about 

 as wide as the ribs, terminating a little above the sutures. Sutures 

 well impressed, rendered slightly sinuous by the ribs. Periphery of 

 the last whorl and the moderately long base, somewhat inflated and 

 well rounded. Entire surface of base and spire marked by very fine 

 closely spaced spiral striations. Aperture pear-shaped; posterior 

 angle acute; outer lip thin, showing the external sculpture within; 

 columella strong, almost straight, decidedly revolute, reenforced for 

 half its length by the base. 



