104 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



TURBONILLA (PYRGISCUS) CRATICULATA Morch. 



Plate 10, figs. 1, lo. 

 Turbonilla craticulata MoacH, Malak. Blatt., vol. 6, 1859, p. 119. 



Shell elongate-conic, brown. Nuclear whorls one and one-third, 

 forming a depressed helicoid spire, whose axis is at right angles to 

 that of the succeeding turns, in the first of which it is about one-fifth 

 immersed. Post-nuclear whorls moderately rounded, slightly con- 

 tracted at the periphery, and weakly shouldered at the summit; 

 marked by moderately strong, straight, very regular, almost vertical 

 axial ribs, of which 14 occur upon the first to third, 16 upon the third 

 to sixth, 18 upon the seventh to ninth, and 22 upon the penultimate 

 turn. Intercostal spaces a little wider than the ribs, marked by 

 seven series of pits, which are a little wider than the raised spaces 

 that separate them. The third of these pits anterior to the summit 

 is a little stronger than the rest; the remainder are of equal strength 

 and spacing. Sutures well impressed. Periphery and base of the 

 last whorl well rounded, marked by the feeble continuations of the 

 axial ribs. The base is marked by incised spiral lines, the first two 

 anterior to the periphery being similar in character to those between 

 the sutures; the rest are successively finer from the periphery to 

 the umbilical region. Aperture ovate, somewhat effuse anteriorly, 

 posterior angle acute; outer lip thin, shomng the external sculpture 

 within; columella oblique, slightly curved, and very strongly revo- 

 lute, provided with a strong oblique fold a little anterior to its inser- 

 tion; parietal wall covered by a thin callus. 



Three specimens were dredged by Dr. A. S. Oersted in 30 fathoms 

 at Los Bocorones, a small island near Punta Arenas, Costa Rica. 

 This is Doctor Morch's type lot in the museum in Copenhagen, Den- 

 mark. Our description and figure are taken from the most perfect 

 specimen, which has eleven post-nuclear whorls, and measures: 

 Length 7.8 mm., diameter 2. mm. 



TURBONILLA (PYRGISCUS) CERALVA, new species. 

 Plate 10, ligs. 5, 5a. 



Shell small, slender, milk-white. Nuclear whorls one and three- 

 fourths, depressed, helicoid, having their axis at right angles to that 

 of the succeeding turns, not immersed. Post-nuclear whorls very 

 high between the sutures, moderately rounded, very slightly shoul- 

 dered at the summit, and somewhat contracted at the sutures, 

 marked by slender, curved, rounded, decidedly retractive axial ribs, 

 which are very feebly expressed on the first whorl, on all the rest 

 excepting the penultimate, which has 40, there are 36. Intercostal 

 spaces al)Out as wide as the ribs, marked by seven equal and equally 

 spaced spiral pits. Periphery and base of the last whorl well rounded, 



