130 BULLETIN 68^ UNITED STATES NATIONAL MUSEUM. 



TURBONILLA (ASMUNDA) TURRITA C. B. Adams. 



Plate 12, figs. 14, 14a. 



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

 pp. 393, 394. 



Shell elongate-conic, milk-white. Nuclear whorls small, two and 

 one-half, forming an elevated helicoid spire, whose axis is at right 

 angles to that of the succeeding turns, in the first of which it is about 

 one-third immersed. Post-nuclear whorls moderately well rountied, 

 with a very broad, flat, tabulated summit, marked by strong, lamellar, 

 somewhat sinuous, almost vertical axial ribs, of which 18 occur 

 upon the flrst, 14 upon the second to fifth, 16 upon the sixth, 18 upon 

 the seventh, 20 upon the eighth, and 24 upon the penultimate whorl. 

 Intercostal spaces about four times as wide as the ribs, deeply 

 impressed, smooth. Sutures very strongly marked. Periphery of 

 the last whorl marked by a strong keel, middle of the base with a 

 strong tumid fasciole, the space between which and the periphery 

 forms a shallow, well-rounded channel. Umbilical area slightly 

 excavated. In addition to this sculpture, the base is crossed by 

 many, subequal, slender, raised axial threads, which do not corre- 

 spond to the axial ribs, between the sutures. Aperture irregular; 

 posterior angle obtuse; outer lip thin, showing the external sculpture 

 within; columella strong and slightly curved. 



Cat. no. 230 of Professor Adams's Panama Shells, in Amherst Col- 

 lege, contains two specimens, the cotypes. We have selected the 

 better of the two for our description and figure. This has 10 post- 

 nuclear whorls and measures: Length 4.7 mm., diameter 1.3 mm. 

 In the same collection, no. 251, Rissoa, sp. indet., a fragment, belongs 



here. 



Subgenus CARELIOPSIS Morch. 



Careliopsis MoRCB., Malak. Blatt., 1874, p. 169. 



Turbonillas having the surface marked by many subequal well- 

 impress(^d spiral lines and numerous feeble axial riblets. Under low 

 magnification the sculpture appears to consist of impressed pitted 

 spiral lines only. 



Tyj^e. — Mono'ptygma (Careliopsis) styliformis Morch. 



TURBONILLA (CARELIOPSIS) STENOGYRA, new species. 

 Plate 12, figs. 1, la. 



Shell acicular, transparent. Nuclear whorls small, two, formmg 

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

 the succeeding turns, in the first of which it is very slightly immersed. 

 Post-nuclear whorls slightly rounded, somewhat contracted imme- 

 diately below the sutures which causes the summits to appear some- 

 what exserted. The first three post-nuclear whorls show traces of 



